diff --git a/cmd/restic/global.go b/cmd/restic/global.go
index b218eacde..391e1edf6 100644
--- a/cmd/restic/global.go
+++ b/cmd/restic/global.go
@@ -414,7 +414,7 @@ func OpenRepository(ctx context.Context, opts GlobalOptions, printer progress.Pr
 	}
 
 	// start using the cache
-	s.UseCache(c)
+	s.UseCache(c, printer.E)
 
 	oldCacheDirs, err := cache.Old(c.Base)
 	if err != nil {
@@ -492,9 +492,9 @@ func innerOpen(ctx context.Context, s string, gopts GlobalOptions, opts options.
 
 	var be backend.Backend
 	if create {
-		be, err = factory.Create(ctx, cfg, rt, lim)
+		be, err = factory.Create(ctx, cfg, rt, lim, printer.E)
 	} else {
-		be, err = factory.Open(ctx, cfg, rt, lim)
+		be, err = factory.Open(ctx, cfg, rt, lim, printer.E)
 	}
 
 	if errors.Is(err, backend.ErrNoRepository) {
diff --git a/internal/backend/azure/azure.go b/internal/backend/azure/azure.go
index c2dc336cd..46df66113 100644
--- a/internal/backend/azure/azure.go
+++ b/internal/backend/azure/azure.go
@@ -159,13 +159,13 @@ func supportedAccessTiers() []blob.AccessTier {
 }
 
 // Open opens the Azure backend at specified container.
-func Open(_ context.Context, cfg Config, rt http.RoundTripper) (*Backend, error) {
+func Open(_ context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (*Backend, error) {
 	return open(cfg, rt)
 }
 
 // Create opens the Azure backend at specified container and creates the container if
 // it does not exist yet.
-func Create(ctx context.Context, cfg Config, rt http.RoundTripper) (*Backend, error) {
+func Create(ctx context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (*Backend, error) {
 	be, err := open(cfg, rt)
 
 	if err != nil {
diff --git a/internal/backend/azure/azure_test.go b/internal/backend/azure/azure_test.go
index adafb6b03..f755b21d2 100644
--- a/internal/backend/azure/azure_test.go
+++ b/internal/backend/azure/azure_test.go
@@ -116,7 +116,7 @@ func TestBackendAzureAccountToken(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	_, err = azure.Create(ctx, *cfg, tr)
+	_, err = azure.Create(ctx, *cfg, tr, t.Logf)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -159,7 +159,7 @@ func TestBackendAzureContainerToken(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	_, err = azure.Create(ctx, *cfg, tr)
+	_, err = azure.Create(ctx, *cfg, tr, t.Logf)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -193,7 +193,7 @@ func TestUploadLargeFile(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	be, err := azure.Create(ctx, *cfg, tr)
+	be, err := azure.Create(ctx, *cfg, tr, t.Logf)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/internal/backend/b2/b2.go b/internal/backend/b2/b2.go
index 6ebba570e..6e751479d 100644
--- a/internal/backend/b2/b2.go
+++ b/internal/backend/b2/b2.go
@@ -88,7 +88,7 @@ func newClient(ctx context.Context, cfg Config, rt http.RoundTripper) (*b2.Clien
 }
 
 // Open opens a connection to the B2 service.
-func Open(ctx context.Context, cfg Config, rt http.RoundTripper) (backend.Backend, error) {
+func Open(ctx context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (backend.Backend, error) {
 	debug.Log("cfg %#v", cfg)
 
 	ctx, cancel := context.WithCancel(ctx)
@@ -120,7 +120,7 @@ func Open(ctx context.Context, cfg Config, rt http.RoundTripper) (backend.Backen
 
 // Create opens a connection to the B2 service. If the bucket does not exist yet,
 // it is created.
-func Create(ctx context.Context, cfg Config, rt http.RoundTripper) (backend.Backend, error) {
+func Create(ctx context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (backend.Backend, error) {
 	debug.Log("cfg %#v", cfg)
 
 	ctx, cancel := context.WithCancel(ctx)
diff --git a/internal/backend/cache/backend.go b/internal/backend/cache/backend.go
index f323b1663..8a561c411 100644
--- a/internal/backend/cache/backend.go
+++ b/internal/backend/cache/backend.go
@@ -2,9 +2,7 @@ package cache
 
 import (
 	"context"
-	"fmt"
 	"io"
-	"os"
 	"sync"
 
 	"github.com/restic/restic/internal/backend"
@@ -22,16 +20,18 @@ type Backend struct {
 	// is finished.
 	inProgressMutex sync.Mutex
 	inProgress      map[backend.Handle]chan struct{}
+	errorLog        func(string, ...interface{})
 }
 
 // ensure Backend implements backend.Backend
 var _ backend.Backend = &Backend{}
 
-func newBackend(be backend.Backend, c *Cache) *Backend {
+func newBackend(be backend.Backend, c *Cache, errorLog func(string, ...interface{})) *Backend {
 	return &Backend{
 		Backend:    be,
 		Cache:      c,
 		inProgress: make(map[backend.Handle]chan struct{}),
+		errorLog:   errorLog,
 	}
 }
 
@@ -253,7 +253,7 @@ func (b *Backend) List(ctx context.Context, t backend.FileType, fn func(f backen
 	// clear the cache for files that are not in the repo anymore, ignore errors
 	err = b.Cache.Clear(t, ids)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "error clearing %s files in cache: %v\n", t.String(), err)
+		b.errorLog("error clearing %s files in cache: %v\n", t.String(), err)
 	}
 
 	return nil
diff --git a/internal/backend/cache/backend_test.go b/internal/backend/cache/backend_test.go
index 7f83e40cb..12d4fa028 100644
--- a/internal/backend/cache/backend_test.go
+++ b/internal/backend/cache/backend_test.go
@@ -67,7 +67,7 @@ func list(t testing.TB, be backend.Backend, fn func(backend.FileInfo) error) {
 func TestBackend(t *testing.T) {
 	be := mem.New()
 	c := TestNewCache(t)
-	wbe := c.Wrap(be)
+	wbe := c.Wrap(be, t.Logf)
 
 	h, data := randomData(5234142)
 
@@ -135,7 +135,7 @@ func (l *loadCountingBackend) Load(ctx context.Context, h backend.Handle, length
 func TestOutOfBoundsAccess(t *testing.T) {
 	be := &loadCountingBackend{Backend: mem.New()}
 	c := TestNewCache(t)
-	wbe := c.Wrap(be)
+	wbe := c.Wrap(be, t.Logf)
 
 	h, data := randomData(50)
 	save(t, be, h, data)
@@ -164,7 +164,7 @@ func TestOutOfBoundsAccess(t *testing.T) {
 func TestForget(t *testing.T) {
 	be := &loadCountingBackend{Backend: mem.New()}
 	c := TestNewCache(t)
-	wbe := c.Wrap(be)
+	wbe := c.Wrap(be, t.Logf)
 
 	h, data := randomData(50)
 	save(t, be, h, data)
@@ -236,7 +236,7 @@ func TestErrorBackend(t *testing.T) {
 		time.Sleep(time.Millisecond)
 	}
 
-	wrappedBE := c.Wrap(errBackend)
+	wrappedBE := c.Wrap(errBackend, t.Logf)
 	var wg sync.WaitGroup
 	for i := 0; i < 5; i++ {
 		wg.Add(1)
@@ -249,7 +249,7 @@ func TestErrorBackend(t *testing.T) {
 func TestAutomaticCacheClear(t *testing.T) {
 	be := mem.New()
 	c := TestNewCache(t)
-	wbe := c.Wrap(be)
+	wbe := c.Wrap(be, t.Logf)
 
 	// add two handles h1 and h2
 	h1, data := randomData(2000)
@@ -308,7 +308,7 @@ func TestAutomaticCacheClearInvalidFilename(t *testing.T) {
 	}
 	save(t, be, h, data)
 
-	wbe := c.Wrap(be)
+	wbe := c.Wrap(be, t.Logf)
 
 	// list all files in the backend
 	list(t, wbe, func(_ backend.FileInfo) error { return nil })
diff --git a/internal/backend/cache/cache.go b/internal/backend/cache/cache.go
index 2893df501..d1bfa47a0 100644
--- a/internal/backend/cache/cache.go
+++ b/internal/backend/cache/cache.go
@@ -237,8 +237,8 @@ func IsOld(t time.Time, maxAge time.Duration) bool {
 }
 
 // Wrap returns a backend with a cache.
-func (c *Cache) Wrap(be backend.Backend) backend.Backend {
-	return newBackend(be, c)
+func (c *Cache) Wrap(be backend.Backend, errorLog func(string, ...interface{})) backend.Backend {
+	return newBackend(be, c, errorLog)
 }
 
 // BaseDir returns the base directory.
diff --git a/internal/backend/gs/gs.go b/internal/backend/gs/gs.go
index 9ea5fca2b..aaf1ae33c 100644
--- a/internal/backend/gs/gs.go
+++ b/internal/backend/gs/gs.go
@@ -120,7 +120,7 @@ func open(cfg Config, rt http.RoundTripper) (*Backend, error) {
 }
 
 // Open opens the gs backend at the specified bucket.
-func Open(_ context.Context, cfg Config, rt http.RoundTripper) (backend.Backend, error) {
+func Open(_ context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (backend.Backend, error) {
 	return open(cfg, rt)
 }
 
@@ -129,7 +129,7 @@ func Open(_ context.Context, cfg Config, rt http.RoundTripper) (backend.Backend,
 //
 // The service account must have the "storage.buckets.create" permission to
 // create a bucket the does not yet exist.
-func Create(ctx context.Context, cfg Config, rt http.RoundTripper) (backend.Backend, error) {
+func Create(ctx context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (backend.Backend, error) {
 	be, err := open(cfg, rt)
 	if err != nil {
 		return nil, err
diff --git a/internal/backend/limiter/limiter_backend.go b/internal/backend/limiter/limiter_backend.go
index ac1a4188a..945777688 100644
--- a/internal/backend/limiter/limiter_backend.go
+++ b/internal/backend/limiter/limiter_backend.go
@@ -7,10 +7,10 @@ import (
 	"github.com/restic/restic/internal/backend"
 )
 
-func WrapBackendConstructor[B backend.Backend, C any](constructor func(ctx context.Context, cfg C) (B, error)) func(ctx context.Context, cfg C, lim Limiter) (backend.Backend, error) {
-	return func(ctx context.Context, cfg C, lim Limiter) (backend.Backend, error) {
+func WrapBackendConstructor[B backend.Backend, C any](constructor func(ctx context.Context, cfg C, errorLog func(string, ...interface{})) (B, error)) func(ctx context.Context, cfg C, lim Limiter, errorLog func(string, ...interface{})) (backend.Backend, error) {
+	return func(ctx context.Context, cfg C, lim Limiter, errorLog func(string, ...interface{})) (backend.Backend, error) {
 		var be backend.Backend
-		be, err := constructor(ctx, cfg)
+		be, err := constructor(ctx, cfg, errorLog)
 		if err != nil {
 			return nil, err
 		}
diff --git a/internal/backend/local/layout_test.go b/internal/backend/local/layout_test.go
index cac89e552..56219f608 100644
--- a/internal/backend/local/layout_test.go
+++ b/internal/backend/local/layout_test.go
@@ -32,7 +32,7 @@ func TestLayout(t *testing.T) {
 			be, err := Open(context.TODO(), Config{
 				Path:        repo,
 				Connections: 2,
-			})
+			}, t.Logf)
 			if err != nil {
 				t.Fatal(err)
 			}
diff --git a/internal/backend/local/local.go b/internal/backend/local/local.go
index 861371b3e..1c1a13470 100644
--- a/internal/backend/local/local.go
+++ b/internal/backend/local/local.go
@@ -52,14 +52,14 @@ func open(cfg Config) (*Local, error) {
 }
 
 // Open opens the local backend as specified by config.
-func Open(_ context.Context, cfg Config) (*Local, error) {
+func Open(_ context.Context, cfg Config, _ func(string, ...interface{})) (*Local, error) {
 	debug.Log("open local backend at %v", cfg.Path)
 	return open(cfg)
 }
 
 // Create creates all the necessary files and directories for a new local
 // backend at dir. Afterwards a new config blob should be created.
-func Create(_ context.Context, cfg Config) (*Local, error) {
+func Create(_ context.Context, cfg Config, _ func(string, ...interface{})) (*Local, error) {
 	debug.Log("create local backend at %v", cfg.Path)
 
 	be, err := open(cfg)
diff --git a/internal/backend/local/local_internal_test.go b/internal/backend/local/local_internal_test.go
index 6cad26d0a..6a7616031 100644
--- a/internal/backend/local/local_internal_test.go
+++ b/internal/backend/local/local_internal_test.go
@@ -26,7 +26,7 @@ func TestNoSpacePermanent(t *testing.T) {
 
 	dir := rtest.TempDir(t)
 
-	be, err := Open(context.Background(), Config{Path: dir, Connections: 2})
+	be, err := Open(context.Background(), Config{Path: dir, Connections: 2}, t.Logf)
 	rtest.OK(t, err)
 	defer func() {
 		rtest.OK(t, be.Close())
diff --git a/internal/backend/local/local_test.go b/internal/backend/local/local_test.go
index 2a8b626d4..f47f27920 100644
--- a/internal/backend/local/local_test.go
+++ b/internal/backend/local/local_test.go
@@ -66,7 +66,7 @@ func empty(t testing.TB, dir string) {
 func openclose(t testing.TB, dir string) {
 	cfg := local.Config{Path: dir}
 
-	be, err := local.Open(context.TODO(), cfg)
+	be, err := local.Open(context.TODO(), cfg, t.Logf)
 	if err != nil {
 		t.Logf("Open returned error %v", err)
 	}
diff --git a/internal/backend/location/registry.go b/internal/backend/location/registry.go
index b50371add..c0761e76b 100644
--- a/internal/backend/location/registry.go
+++ b/internal/backend/location/registry.go
@@ -33,16 +33,16 @@ type Factory interface {
 	Scheme() string
 	ParseConfig(s string) (interface{}, error)
 	StripPassword(s string) string
-	Create(ctx context.Context, cfg interface{}, rt http.RoundTripper, lim limiter.Limiter) (backend.Backend, error)
-	Open(ctx context.Context, cfg interface{}, rt http.RoundTripper, lim limiter.Limiter) (backend.Backend, error)
+	Create(ctx context.Context, cfg interface{}, rt http.RoundTripper, lim limiter.Limiter, errorLog func(string, ...interface{})) (backend.Backend, error)
+	Open(ctx context.Context, cfg interface{}, rt http.RoundTripper, lim limiter.Limiter, errorLog func(string, ...interface{})) (backend.Backend, error)
 }
 
 type genericBackendFactory[C any, T backend.Backend] struct {
 	scheme          string
 	parseConfigFn   func(s string) (*C, error)
 	stripPasswordFn func(s string) string
-	createFn        func(ctx context.Context, cfg C, rt http.RoundTripper, lim limiter.Limiter) (T, error)
-	openFn          func(ctx context.Context, cfg C, rt http.RoundTripper, lim limiter.Limiter) (T, error)
+	createFn        func(ctx context.Context, cfg C, rt http.RoundTripper, lim limiter.Limiter, errorLog func(string, ...interface{})) (T, error)
+	openFn          func(ctx context.Context, cfg C, rt http.RoundTripper, lim limiter.Limiter, errorLog func(string, ...interface{})) (T, error)
 }
 
 func (f *genericBackendFactory[C, T]) Scheme() string {
@@ -58,29 +58,29 @@ func (f *genericBackendFactory[C, T]) StripPassword(s string) string {
 	}
 	return s
 }
-func (f *genericBackendFactory[C, T]) Create(ctx context.Context, cfg interface{}, rt http.RoundTripper, lim limiter.Limiter) (backend.Backend, error) {
-	return f.createFn(ctx, *cfg.(*C), rt, lim)
+func (f *genericBackendFactory[C, T]) Create(ctx context.Context, cfg interface{}, rt http.RoundTripper, lim limiter.Limiter, errorLog func(string, ...interface{})) (backend.Backend, error) {
+	return f.createFn(ctx, *cfg.(*C), rt, lim, errorLog)
 }
-func (f *genericBackendFactory[C, T]) Open(ctx context.Context, cfg interface{}, rt http.RoundTripper, lim limiter.Limiter) (backend.Backend, error) {
-	return f.openFn(ctx, *cfg.(*C), rt, lim)
+func (f *genericBackendFactory[C, T]) Open(ctx context.Context, cfg interface{}, rt http.RoundTripper, lim limiter.Limiter, errorLog func(string, ...interface{})) (backend.Backend, error) {
+	return f.openFn(ctx, *cfg.(*C), rt, lim, errorLog)
 }
 
 func NewHTTPBackendFactory[C any, T backend.Backend](
 	scheme string,
 	parseConfigFn func(s string) (*C, error),
 	stripPasswordFn func(s string) string,
-	createFn func(ctx context.Context, cfg C, rt http.RoundTripper) (T, error),
-	openFn func(ctx context.Context, cfg C, rt http.RoundTripper) (T, error)) Factory {
+	createFn func(ctx context.Context, cfg C, rt http.RoundTripper, errorLog func(string, ...interface{})) (T, error),
+	openFn func(ctx context.Context, cfg C, rt http.RoundTripper, errorLog func(string, ...interface{})) (T, error)) Factory {
 
 	return &genericBackendFactory[C, T]{
 		scheme:          scheme,
 		parseConfigFn:   parseConfigFn,
 		stripPasswordFn: stripPasswordFn,
-		createFn: func(ctx context.Context, cfg C, rt http.RoundTripper, _ limiter.Limiter) (T, error) {
-			return createFn(ctx, cfg, rt)
+		createFn: func(ctx context.Context, cfg C, rt http.RoundTripper, _ limiter.Limiter, errorLog func(string, ...interface{})) (T, error) {
+			return createFn(ctx, cfg, rt, errorLog)
 		},
-		openFn: func(ctx context.Context, cfg C, rt http.RoundTripper, _ limiter.Limiter) (T, error) {
-			return openFn(ctx, cfg, rt)
+		openFn: func(ctx context.Context, cfg C, rt http.RoundTripper, _ limiter.Limiter, errorLog func(string, ...interface{})) (T, error) {
+			return openFn(ctx, cfg, rt, errorLog)
 		},
 	}
 }
@@ -89,18 +89,18 @@ func NewLimitedBackendFactory[C any, T backend.Backend](
 	scheme string,
 	parseConfigFn func(s string) (*C, error),
 	stripPasswordFn func(s string) string,
-	createFn func(ctx context.Context, cfg C, lim limiter.Limiter) (T, error),
-	openFn func(ctx context.Context, cfg C, lim limiter.Limiter) (T, error)) Factory {
+	createFn func(ctx context.Context, cfg C, lim limiter.Limiter, errorLog func(string, ...interface{})) (T, error),
+	openFn func(ctx context.Context, cfg C, lim limiter.Limiter, errorLog func(string, ...interface{})) (T, error)) Factory {
 
 	return &genericBackendFactory[C, T]{
 		scheme:          scheme,
 		parseConfigFn:   parseConfigFn,
 		stripPasswordFn: stripPasswordFn,
-		createFn: func(ctx context.Context, cfg C, _ http.RoundTripper, lim limiter.Limiter) (T, error) {
-			return createFn(ctx, cfg, lim)
+		createFn: func(ctx context.Context, cfg C, _ http.RoundTripper, lim limiter.Limiter, errorLog func(string, ...interface{})) (T, error) {
+			return createFn(ctx, cfg, lim, errorLog)
 		},
-		openFn: func(ctx context.Context, cfg C, _ http.RoundTripper, lim limiter.Limiter) (T, error) {
-			return openFn(ctx, cfg, lim)
+		openFn: func(ctx context.Context, cfg C, _ http.RoundTripper, lim limiter.Limiter, errorLog func(string, ...interface{})) (T, error) {
+			return openFn(ctx, cfg, lim, errorLog)
 		},
 	}
 }
diff --git a/internal/backend/mem/mem_backend.go b/internal/backend/mem/mem_backend.go
index 3064a3b88..6ff38867c 100644
--- a/internal/backend/mem/mem_backend.go
+++ b/internal/backend/mem/mem_backend.go
@@ -33,10 +33,10 @@ func NewFactory() location.Factory {
 			return &struct{}{}, nil
 		},
 		location.NoPassword,
-		func(_ context.Context, _ struct{}, _ http.RoundTripper) (*MemoryBackend, error) {
+		func(_ context.Context, _ struct{}, _ http.RoundTripper, _ func(string, ...interface{})) (*MemoryBackend, error) {
 			return be, nil
 		},
-		func(_ context.Context, _ struct{}, _ http.RoundTripper) (*MemoryBackend, error) {
+		func(_ context.Context, _ struct{}, _ http.RoundTripper, _ func(string, ...interface{})) (*MemoryBackend, error) {
 			return be, nil
 		},
 	)
diff --git a/internal/backend/rclone/backend.go b/internal/backend/rclone/backend.go
index 5ee330a69..afc516355 100644
--- a/internal/backend/rclone/backend.go
+++ b/internal/backend/rclone/backend.go
@@ -43,7 +43,7 @@ func NewFactory() location.Factory {
 }
 
 // run starts command with args and initializes the StdioConn.
-func run(command string, args ...string) (*StdioConn, *sync.WaitGroup, chan struct{}, func() error, error) {
+func run(errorLog func(string, ...interface{}), command string, args ...string) (*StdioConn, *sync.WaitGroup, chan struct{}, func() error, error) {
 	cmd := exec.Command(command, args...)
 
 	p, err := cmd.StderrPipe()
@@ -61,7 +61,7 @@ func run(command string, args ...string) (*StdioConn, *sync.WaitGroup, chan stru
 		defer close(waitCh)
 		sc := bufio.NewScanner(p)
 		for sc.Scan() {
-			fmt.Fprintf(os.Stderr, "rclone: %v\n", sc.Text())
+			errorLog("rclone: %v\n", sc.Text())
 		}
 		debug.Log("command has exited, closing waitCh")
 	}()
@@ -140,7 +140,7 @@ func wrapConn(c *StdioConn, lim limiter.Limiter) *wrappedConn {
 }
 
 // New initializes a Backend and starts the process.
-func newBackend(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend, error) {
+func newBackend(ctx context.Context, cfg Config, lim limiter.Limiter, errorLog func(string, ...interface{})) (*Backend, error) {
 	var (
 		args []string
 		err  error
@@ -170,7 +170,7 @@ func newBackend(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend,
 	arg0, args := args[0], args[1:]
 
 	debug.Log("running command: %v %v", arg0, args)
-	stdioConn, wg, waitCh, bg, err := run(arg0, args...)
+	stdioConn, wg, waitCh, bg, err := run(errorLog, arg0, args...)
 	if err != nil {
 		return nil, err
 	}
@@ -263,8 +263,8 @@ func newBackend(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend,
 }
 
 // Open starts an rclone process with the given config.
-func Open(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend, error) {
-	be, err := newBackend(ctx, cfg, lim)
+func Open(ctx context.Context, cfg Config, lim limiter.Limiter, errorLog func(string, ...interface{})) (*Backend, error) {
+	be, err := newBackend(ctx, cfg, lim, errorLog)
 	if err != nil {
 		return nil, err
 	}
@@ -279,7 +279,7 @@ func Open(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend, error
 		URL:         url,
 	}
 
-	restBackend, err := rest.Open(ctx, restConfig, debug.RoundTripper(be.tr))
+	restBackend, err := rest.Open(ctx, restConfig, debug.RoundTripper(be.tr), errorLog)
 	if err != nil {
 		_ = be.Close()
 		return nil, err
@@ -290,8 +290,8 @@ func Open(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend, error
 }
 
 // Create initializes a new restic repo with rclone.
-func Create(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend, error) {
-	be, err := newBackend(ctx, cfg, lim)
+func Create(ctx context.Context, cfg Config, lim limiter.Limiter, errorLog func(string, ...interface{})) (*Backend, error) {
+	be, err := newBackend(ctx, cfg, lim, errorLog)
 	if err != nil {
 		return nil, err
 	}
@@ -308,7 +308,7 @@ func Create(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend, err
 		URL:         url,
 	}
 
-	restBackend, err := rest.Create(ctx, restConfig, debug.RoundTripper(be.tr))
+	restBackend, err := rest.Create(ctx, restConfig, debug.RoundTripper(be.tr), errorLog)
 	if err != nil {
 		_ = be.Close()
 		return nil, err
diff --git a/internal/backend/rclone/internal_test.go b/internal/backend/rclone/internal_test.go
index 34d52885e..adc251557 100644
--- a/internal/backend/rclone/internal_test.go
+++ b/internal/backend/rclone/internal_test.go
@@ -15,7 +15,7 @@ func TestRcloneExit(t *testing.T) {
 	dir := rtest.TempDir(t)
 	cfg := NewConfig()
 	cfg.Remote = dir
-	be, err := Open(context.TODO(), cfg, nil)
+	be, err := Open(context.TODO(), cfg, nil, t.Logf)
 	var e *exec.Error
 	if errors.As(err, &e) && e.Err == exec.ErrNotFound {
 		t.Skipf("program %q not found", e.Name)
@@ -45,7 +45,7 @@ func TestRcloneFailedStart(t *testing.T) {
 	cfg := NewConfig()
 	// exits with exit code 1
 	cfg.Program = "false"
-	_, err := Open(context.TODO(), cfg, nil)
+	_, err := Open(context.TODO(), cfg, nil, t.Logf)
 	var e *exec.ExitError
 	if !errors.As(err, &e) {
 		// unexpected error
diff --git a/internal/backend/rest/rest.go b/internal/backend/rest/rest.go
index 5776f284f..d0158ab58 100644
--- a/internal/backend/rest/rest.go
+++ b/internal/backend/rest/rest.go
@@ -55,7 +55,7 @@ const (
 )
 
 // Open opens the REST backend with the given config.
-func Open(_ context.Context, cfg Config, rt http.RoundTripper) (*Backend, error) {
+func Open(_ context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (*Backend, error) {
 	// use url without trailing slash for layout
 	url := cfg.URL.String()
 	if url[len(url)-1] == '/' {
@@ -84,8 +84,8 @@ func drainAndClose(resp *http.Response) error {
 }
 
 // Create creates a new REST on server configured in config.
-func Create(ctx context.Context, cfg Config, rt http.RoundTripper) (*Backend, error) {
-	be, err := Open(ctx, cfg, rt)
+func Create(ctx context.Context, cfg Config, rt http.RoundTripper, errorLog func(string, ...interface{})) (*Backend, error) {
+	be, err := Open(ctx, cfg, rt, errorLog)
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/backend/rest/rest_int_test.go b/internal/backend/rest/rest_int_test.go
index 926b30ed4..e7b9eb965 100644
--- a/internal/backend/rest/rest_int_test.go
+++ b/internal/backend/rest/rest_int_test.go
@@ -117,7 +117,7 @@ func TestListAPI(t *testing.T) {
 				URL:         srvURL,
 			}
 
-			be, err := rest.Open(context.TODO(), cfg, http.DefaultTransport)
+			be, err := rest.Open(context.TODO(), cfg, http.DefaultTransport, t.Logf)
 			if err != nil {
 				t.Fatal(err)
 			}
diff --git a/internal/backend/rest/rest_test.go b/internal/backend/rest/rest_test.go
index 50560f66d..109259b92 100644
--- a/internal/backend/rest/rest_test.go
+++ b/internal/backend/rest/rest_test.go
@@ -106,7 +106,7 @@ func runRESTServer(ctx context.Context, t testing.TB, dir, reqListenAddr string)
 					matched = true
 				}
 			}
-			_, _ = fmt.Fprintln(os.Stdout, line) // print all output to console
+			t.Log(line)
 		}
 	}()
 
diff --git a/internal/backend/s3/s3.go b/internal/backend/s3/s3.go
index 3653c827c..cac72144d 100644
--- a/internal/backend/s3/s3.go
+++ b/internal/backend/s3/s3.go
@@ -195,13 +195,13 @@ func getCredentials(cfg Config, tr http.RoundTripper) (*credentials.Credentials,
 
 // Open opens the S3 backend at bucket and region. The bucket is created if it
 // does not exist yet.
-func Open(_ context.Context, cfg Config, rt http.RoundTripper) (backend.Backend, error) {
+func Open(_ context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (backend.Backend, error) {
 	return open(cfg, rt)
 }
 
 // Create opens the S3 backend at bucket and region and creates the bucket if
 // it does not exist yet.
-func Create(ctx context.Context, cfg Config, rt http.RoundTripper) (backend.Backend, error) {
+func Create(ctx context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (backend.Backend, error) {
 	be, err := open(cfg, rt)
 	if err != nil {
 		return nil, errors.Wrap(err, "open")
diff --git a/internal/backend/s3/s3_test.go b/internal/backend/s3/s3_test.go
index 40f7cb0b3..b026ce427 100644
--- a/internal/backend/s3/s3_test.go
+++ b/internal/backend/s3/s3_test.go
@@ -117,9 +117,9 @@ func newMinioTestSuite(t testing.TB) (*test.Suite[s3.Config], func()) {
 				return &cfg, nil
 			},
 
-			Factory: location.NewHTTPBackendFactory("s3", s3.ParseConfig, location.NoPassword, func(ctx context.Context, cfg s3.Config, rt http.RoundTripper) (be backend.Backend, err error) {
+			Factory: location.NewHTTPBackendFactory("s3", s3.ParseConfig, location.NoPassword, func(ctx context.Context, cfg s3.Config, rt http.RoundTripper, errorLog func(string, ...interface{})) (be backend.Backend, err error) {
 				for i := 0; i < 50; i++ {
-					be, err = s3.Create(ctx, cfg, rt)
+					be, err = s3.Create(ctx, cfg, rt, errorLog)
 					if err != nil {
 						t.Logf("s3 open: try %d: error %v", i, err)
 						time.Sleep(500 * time.Millisecond)
diff --git a/internal/backend/sftp/layout_test.go b/internal/backend/sftp/layout_test.go
index 9e143d4fd..c87e3a9d3 100644
--- a/internal/backend/sftp/layout_test.go
+++ b/internal/backend/sftp/layout_test.go
@@ -39,7 +39,7 @@ func TestLayout(t *testing.T) {
 				Command:     fmt.Sprintf("%q -e", sftpServer),
 				Path:        repo,
 				Connections: 5,
-			})
+			}, t.Logf)
 			if err != nil {
 				t.Fatal(err)
 			}
diff --git a/internal/backend/sftp/sftp.go b/internal/backend/sftp/sftp.go
index 174877b26..269a9f41a 100644
--- a/internal/backend/sftp/sftp.go
+++ b/internal/backend/sftp/sftp.go
@@ -51,7 +51,7 @@ func NewFactory() location.Factory {
 	return location.NewLimitedBackendFactory("sftp", ParseConfig, location.NoPassword, limiter.WrapBackendConstructor(Create), limiter.WrapBackendConstructor(Open))
 }
 
-func startClient(cfg Config) (*SFTP, error) {
+func startClient(cfg Config, errorLog func(string, ...interface{})) (*SFTP, error) {
 	program, args, err := buildSSHCommand(cfg)
 	if err != nil {
 		return nil, err
@@ -71,7 +71,7 @@ func startClient(cfg Config) (*SFTP, error) {
 	go func() {
 		sc := bufio.NewScanner(stderr)
 		for sc.Scan() {
-			fmt.Fprintf(os.Stderr, "subprocess %v: %v\n", program, sc.Text())
+			errorLog("subprocess %v: %v\n", program, sc.Text())
 		}
 	}()
 
@@ -144,10 +144,10 @@ func (r *SFTP) clientError() error {
 
 // Open opens an sftp backend as described by the config by running
 // "ssh" with the appropriate arguments (or cfg.Command, if set).
-func Open(_ context.Context, cfg Config) (*SFTP, error) {
+func Open(_ context.Context, cfg Config, errorLog func(string, ...interface{})) (*SFTP, error) {
 	debug.Log("open backend with config %#v", cfg)
 
-	sftp, err := startClient(cfg)
+	sftp, err := startClient(cfg, errorLog)
 	if err != nil {
 		debug.Log("unable to start program: %v", err)
 		return nil, err
@@ -240,8 +240,8 @@ func buildSSHCommand(cfg Config) (cmd string, args []string, err error) {
 
 // Create creates an sftp backend as described by the config by running "ssh"
 // with the appropriate arguments (or cfg.Command, if set).
-func Create(ctx context.Context, cfg Config) (*SFTP, error) {
-	sftp, err := startClient(cfg)
+func Create(ctx context.Context, cfg Config, errorLog func(string, ...interface{})) (*SFTP, error) {
+	sftp, err := startClient(cfg, errorLog)
 	if err != nil {
 		debug.Log("unable to start program: %v", err)
 		return nil, err
diff --git a/internal/backend/swift/swift.go b/internal/backend/swift/swift.go
index ae6a13462..155b5041e 100644
--- a/internal/backend/swift/swift.go
+++ b/internal/backend/swift/swift.go
@@ -42,7 +42,7 @@ func NewFactory() location.Factory {
 
 // Open opens the swift backend at a container in region. The container is
 // created if it does not exist yet.
-func Open(ctx context.Context, cfg Config, rt http.RoundTripper) (backend.Backend, error) {
+func Open(ctx context.Context, cfg Config, rt http.RoundTripper, _ func(string, ...interface{})) (backend.Backend, error) {
 	debug.Log("config %#v", cfg)
 
 	be := &beSwift{
diff --git a/internal/backend/test/suite.go b/internal/backend/test/suite.go
index ad8eb4c5d..86acc5cb5 100644
--- a/internal/backend/test/suite.go
+++ b/internal/backend/test/suite.go
@@ -155,13 +155,13 @@ func (s *Suite[C]) RunBenchmarks(b *testing.B) {
 	s.cleanup(b)
 }
 
-func (s *Suite[C]) createOrError() (backend.Backend, error) {
+func (s *Suite[C]) createOrError(t testing.TB) (backend.Backend, error) {
 	tr, err := backend.Transport(backend.TransportOptions{})
 	if err != nil {
 		return nil, fmt.Errorf("cannot create transport for tests: %v", err)
 	}
 
-	be, err := s.Factory.Create(context.TODO(), s.Config, tr, nil)
+	be, err := s.Factory.Create(context.TODO(), s.Config, tr, nil, t.Logf)
 	if err != nil {
 		return nil, err
 	}
@@ -179,7 +179,7 @@ func (s *Suite[C]) createOrError() (backend.Backend, error) {
 }
 
 func (s *Suite[C]) create(t testing.TB) backend.Backend {
-	be, err := s.createOrError()
+	be, err := s.createOrError(t)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -192,7 +192,7 @@ func (s *Suite[C]) open(t testing.TB) backend.Backend {
 		t.Fatalf("cannot create transport for tests: %v", err)
 	}
 
-	be, err := s.Factory.Open(context.TODO(), s.Config, tr, nil)
+	be, err := s.Factory.Open(context.TODO(), s.Config, tr, nil, func(string, ...interface{}) {})
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/internal/backend/test/tests.go b/internal/backend/test/tests.go
index b3deba8da..5c223412b 100644
--- a/internal/backend/test/tests.go
+++ b/internal/backend/test/tests.go
@@ -79,7 +79,7 @@ func (s *Suite[C]) TestCreateWithConfig(t *testing.T) {
 	store(t, b, backend.ConfigFile, []byte("test config"))
 
 	// now create the backend again, this must fail
-	_, err = s.createOrError()
+	_, err = s.createOrError(t)
 	if err == nil {
 		t.Fatalf("expected error not found for creating a backend with an existing config file")
 	}
diff --git a/internal/repository/raw_test.go b/internal/repository/raw_test.go
index ac65a8dc8..81fc25250 100644
--- a/internal/repository/raw_test.go
+++ b/internal/repository/raw_test.go
@@ -87,7 +87,7 @@ func TestLoadRawBrokenWithCache(t *testing.T) {
 	c := cache.TestNewCache(t)
 	repo, err := repository.New(b, repository.Options{})
 	rtest.OK(t, err)
-	repo.UseCache(c)
+	repo.UseCache(c, t.Logf)
 
 	data := rtest.Random(23, 10*KiB)
 	id := restic.Hash(data)
diff --git a/internal/repository/repository.go b/internal/repository/repository.go
index bd2a0b316..39cb5e9c3 100644
--- a/internal/repository/repository.go
+++ b/internal/repository/repository.go
@@ -161,13 +161,13 @@ func (r *Repository) packSize() uint {
 }
 
 // UseCache replaces the backend with the wrapped cache.
-func (r *Repository) UseCache(c *cache.Cache) {
+func (r *Repository) UseCache(c *cache.Cache, errorLog func(string, ...interface{})) {
 	if c == nil {
 		return
 	}
 	debug.Log("using cache")
 	r.cache = c
-	r.be = c.Wrap(r.be)
+	r.be = c.Wrap(r.be, errorLog)
 }
 
 func (r *Repository) Cache() *cache.Cache {
diff --git a/internal/repository/repository_test.go b/internal/repository/repository_test.go
index 2f2d3d1ac..3496b9a2d 100644
--- a/internal/repository/repository_test.go
+++ b/internal/repository/repository_test.go
@@ -207,7 +207,7 @@ func TestLoadBlobBroken(t *testing.T) {
 
 	// setup cache after saving the blob to make sure that the damageOnceBackend damages the cached data
 	c := cache.TestNewCache(t)
-	repo.UseCache(c)
+	repo.UseCache(c, t.Logf)
 
 	data, err := repo.LoadBlob(context.TODO(), restic.TreeBlob, id, nil)
 	rtest.OK(t, err)
@@ -355,7 +355,7 @@ func TestRepositoryLoadUnpackedRetryBroken(t *testing.T) {
 	repodir, cleanup := rtest.Env(t, repoFixture)
 	defer cleanup()
 
-	be, err := local.Open(context.TODO(), local.Config{Path: repodir, Connections: 2})
+	be, err := local.Open(context.TODO(), local.Config{Path: repodir, Connections: 2}, t.Logf)
 	rtest.OK(t, err)
 	repo := repository.TestOpenBackend(t, &damageOnceBackend{Backend: be})
 
@@ -446,7 +446,7 @@ func TestListPack(t *testing.T) {
 
 	// setup cache after saving the blob to make sure that the damageOnceBackend damages the cached data
 	c := cache.TestNewCache(t)
-	repo.UseCache(c)
+	repo.UseCache(c, t.Logf)
 
 	// Forcibly cache pack file
 	packID := repo.LookupBlob(restic.TreeBlob, id)[0].PackID
diff --git a/internal/repository/testing.go b/internal/repository/testing.go
index 5a464e44f..988daba19 100644
--- a/internal/repository/testing.go
+++ b/internal/repository/testing.go
@@ -91,7 +91,7 @@ func TestRepositoryWithVersion(t testing.TB, version uint) (*Repository, restic.
 	if dir != "" {
 		_, err := os.Stat(dir)
 		if err != nil {
-			lbe, err := local.Create(context.TODO(), local.Config{Path: dir})
+			lbe, err := local.Create(context.TODO(), local.Config{Path: dir}, t.Logf)
 			if err != nil {
 				t.Fatalf("error creating local backend at %v: %v", dir, err)
 			}
@@ -115,7 +115,7 @@ func TestFromFixture(t testing.TB, repoFixture string) (*Repository, backend.Bac
 // TestOpenLocal opens a local repository.
 func TestOpenLocal(t testing.TB, dir string) (*Repository, backend.Backend) {
 	var be backend.Backend
-	be, err := local.Open(context.TODO(), local.Config{Path: dir, Connections: 2})
+	be, err := local.Open(context.TODO(), local.Config{Path: dir, Connections: 2}, t.Logf)
 	if err != nil {
 		t.Fatal(err)
 	}