diff --git a/changelog/unreleased/fix-upload-session-bugs.md b/changelog/unreleased/fix-upload-session-bugs.md
new file mode 100644
index 0000000000..bee1b9416b
--- /dev/null
+++ b/changelog/unreleased/fix-upload-session-bugs.md
@@ -0,0 +1,5 @@
+Bugfix: Fix upload session bugs
+
+We fixed an issue that caused a panic when we could not open a file to calculate checksums. Furthermore, we now delete the upload session .lock file on cleanup.
+
+https://github.com/cs3org/reva/pull/4888
diff --git a/pkg/storage/utils/decomposedfs/upload/session.go b/pkg/storage/utils/decomposedfs/upload/session.go
index a83d5f46b5..072e32e3c2 100644
--- a/pkg/storage/utils/decomposedfs/upload/session.go
+++ b/pkg/storage/utils/decomposedfs/upload/session.go
@@ -86,7 +86,10 @@ func (s *OcisSession) Purge(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	defer f.Close()
+	defer func() {
+		f.Close()
+		os.Remove(sessionPath + ".lock")
+	}()
 	if err := os.Remove(sessionPath); err != nil {
 		return err
 	}
diff --git a/pkg/storage/utils/decomposedfs/upload/upload.go b/pkg/storage/utils/decomposedfs/upload/upload.go
index 0c41b8f759..f3a2fed476 100644
--- a/pkg/storage/utils/decomposedfs/upload/upload.go
+++ b/pkg/storage/utils/decomposedfs/upload/upload.go
@@ -115,7 +115,7 @@ func (session *OcisSession) FinishUpload(ctx context.Context) error {
 
 	sha1h, md5h, adler32h, err := node.CalculateChecksums(ctx, session.binPath())
 	if err != nil {
-		log.Info().Err(err).Msg("error copying checksums")
+		return err
 	}
 
 	// compare if they match the sent checksum