diff --git a/server/s3/backend.go b/server/s3/backend.go
index a79dd2285..7acf058d7 100644
--- a/server/s3/backend.go
+++ b/server/s3/backend.go
@@ -451,11 +451,17 @@ func (b *s3Backend) CopyObject(ctx context.Context, srcBucket, srcKey, dstBucket
 	fmeta, _ := op.GetNearestMeta(srcFp)
 	srcNode, err := fs.Get(context.WithValue(ctx, conf.MetaKey, fmeta), srcFp, &fs.GetArgs{})
 	if err != nil {
+		if errs.IsObjectNotFound(err) {
+			return result, gofakes3.KeyNotFound(srcKey)
+		}
 		return result, err
 	}
 
 	c, err := b.GetObject(ctx, srcBucket, srcKey, nil)
 	if err != nil {
+		if errs.IsObjectNotFound(err) {
+			return result, gofakes3.KeyNotFound(srcKey)
+		}
 		return
 	}
 	defer func() {
diff --git a/server/s3/copy_test.go b/server/s3/copy_test.go
new file mode 100644
index 000000000..b9ba4dadb
--- /dev/null
+++ b/server/s3/copy_test.go
@@ -0,0 +1,17 @@
+package s3
+
+import (
+	"context"
+	"testing"
+
+	"github.com/OpenListTeam/gofakes3"
+)
+
+func TestCopyObjectMissingSourceReturnsNoSuchKey(t *testing.T) {
+	b, _ := setupMultipartBackend(t)
+
+	_, err := b.CopyObject(context.Background(), "mp", "missing.txt", "mp", "copy.txt", nil)
+	if code := s3ErrorCode(err); code != gofakes3.ErrNoSuchKey {
+		t.Fatalf("CopyObject() error = %v, want NoSuchKey", code)
+	}
+}