diff --git a/internal/backend/sftp/sftp.go b/internal/backend/sftp/sftp.go
index a65db464c..c735b9b3a 100644
--- a/internal/backend/sftp/sftp.go
+++ b/internal/backend/sftp/sftp.go
@@ -184,7 +184,7 @@ func (r *SFTP) mkdirAllDataSubdirs(ctx context.Context, nconn uint) error {
 			if err := r.c.Mkdir(d); err == nil {
 				return nil
 			}
-			return r.c.MkdirAll(d)
+			return errors.Wrapf(r.c.MkdirAll(d), "MkdirAll %v", d)
 		})
 	}
 
@@ -311,13 +311,17 @@ func (r *SFTP) Save(_ context.Context, h backend.Handle, rd backend.RewindReader
 		}
 	}
 
+	if err != nil {
+		return errors.Wrapf(err, "OpenFile %v", tmpFilename)
+	}
+
 	// pkg/sftp doesn't allow creating with a mode.
 	// Chmod while the file is still empty.
 	if err == nil {
 		err = f.Chmod(r.Modes.File)
-	}
-	if err != nil {
-		return errors.Wrap(err, "OpenFile")
+		if err != nil {
+			return errors.Wrapf(err, "Chmod %v", tmpFilename)
+		}
 	}
 
 	defer func() {
@@ -338,18 +342,18 @@ func (r *SFTP) Save(_ context.Context, h backend.Handle, rd backend.RewindReader
 	if err != nil {
 		_ = f.Close()
 		err = r.checkNoSpace(dirname, rd.Length(), err)
-		return errors.Wrap(err, "Write")
+		return errors.Wrapf(err, "Write %v", tmpFilename)
 	}
 
 	// sanity check
 	if wbytes != rd.Length() {
 		_ = f.Close()
-		return errors.Errorf("wrote %d bytes instead of the expected %d bytes", wbytes, rd.Length())
+		return errors.Errorf("Write %v: wrote %d bytes instead of the expected %d bytes", tmpFilename, wbytes, rd.Length())
 	}
 
 	err = f.Close()
 	if err != nil {
-		return errors.Wrap(err, "Close")
+		return errors.Wrapf(err, "Close %v", tmpFilename)
 	}
 
 	// Prefer POSIX atomic rename if available.
@@ -358,7 +362,7 @@ func (r *SFTP) Save(_ context.Context, h backend.Handle, rd backend.RewindReader
 	} else {
 		err = r.c.Rename(tmpFilename, filename)
 	}
-	return errors.Wrap(err, "Rename")
+	return errors.Wrapf(err, "Rename %v", tmpFilename)
 }
 
 // checkNoSpace checks if err was likely caused by lack of available space
@@ -416,14 +420,14 @@ func (r *SFTP) Load(ctx context.Context, h backend.Handle, length int, offset in
 func (r *SFTP) openReader(_ context.Context, h backend.Handle, length int, offset int64) (io.ReadCloser, error) {
 	f, err := r.c.Open(r.Filename(h))
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrapf(err, "Open %v", r.Filename(h))
 	}
 
 	if offset > 0 {
 		_, err = f.Seek(offset, 0)
 		if err != nil {
 			_ = f.Close()
-			return nil, err
+			return nil, errors.Wrapf(err, "Seek %v", r.Filename(h))
 		}
 	}
 
@@ -444,7 +448,7 @@ func (r *SFTP) Stat(_ context.Context, h backend.Handle) (backend.FileInfo, erro
 
 	fi, err := r.c.Lstat(r.Filename(h))
 	if err != nil {
-		return backend.FileInfo{}, errors.Wrap(err, "Lstat")
+		return backend.FileInfo{}, errors.Wrapf(err, "Lstat %v", r.Filename(h))
 	}
 
 	return backend.FileInfo{Size: fi.Size(), Name: h.Name}, nil
@@ -456,7 +460,7 @@ func (r *SFTP) Remove(_ context.Context, h backend.Handle) error {
 		return err
 	}
 
-	return r.c.Remove(r.Filename(h))
+	return errors.Wrapf(r.c.Remove(r.Filename(h)), "Remove %v", r.Filename(h))
 }
 
 // List runs fn for each file in the backend which has the type t. When an
@@ -479,7 +483,7 @@ func (r *SFTP) List(ctx context.Context, t backend.FileType, fn func(backend.Fil
 				debug.Log("ignoring non-existing directory")
 				return nil
 			}
-			return walker.Err()
+			return errors.Wrapf(walker.Err(), "Walk %v", basedir)
 		}
 
 		if walker.Path() == basedir {
@@ -528,7 +532,7 @@ func (r *SFTP) Close() error {
 		return nil
 	}
 
-	err := r.c.Close()
+	err := errors.Wrap(r.c.Close(), "Close")
 	debug.Log("Close returned error %v", err)
 
 	// wait for closeTimeout before killing the process
@@ -550,7 +554,7 @@ func (r *SFTP) Close() error {
 func (r *SFTP) deleteRecursive(ctx context.Context, name string) error {
 	entries, err := r.c.ReadDir(name)
 	if err != nil {
-		return errors.Wrapf(err, "ReadDir(%v)", name)
+		return errors.Wrapf(err, "ReadDir %v", name)
 	}
 
 	for _, fi := range entries {
@@ -562,12 +566,12 @@ func (r *SFTP) deleteRecursive(ctx context.Context, name string) error {
 		if fi.IsDir() {
 			err := r.deleteRecursive(ctx, itemName)
 			if err != nil {
-				return errors.Wrap(err, "ReadDir")
+				return err
 			}
 
 			err = r.c.RemoveDirectory(itemName)
 			if err != nil {
-				return errors.Wrap(err, "RemoveDirectory")
+				return errors.Wrapf(err, "RemoveDirectory %v", itemName)
 			}
 
 			continue
@@ -575,7 +579,7 @@ func (r *SFTP) deleteRecursive(ctx context.Context, name string) error {
 
 		err := r.c.Remove(itemName)
 		if err != nil {
-			return errors.Wrap(err, "ReadDir")
+			return errors.Wrapf(err, "Remove %v", itemName)
 		}
 	}