diff --git a/api/src/Db/Backup.php b/api/src/Db/Backup.php
index 506f7fbd9c..326e136135 100644
--- a/api/src/Db/Backup.php
+++ b/api/src/Db/Backup.php
@@ -1239,18 +1239,30 @@ class Backup
 	 * Move uploaded file to backup-directory
 	 *
 	 * @param array $file values for keys "tmp_name", "name", "size"
-	 * @return ?string success message or null on error
+	 * @return string success or error message
 	 */
-	public function upload(array $file) : ?string
+	public function upload(array $file) : string
 	{
-		if (move_uploaded_file($file['tmp_name'], $filename = $this->backup_dir . '/' . basename($file['name'])))
+		if (is_uploaded_file($file['tmp_name']) && ($src=fopen($file['tmp_name'], 'r')) &&
+			($dst=fopen($filename = $this->backup_dir . '/' . basename($file['name']), 'w')) &&
+			stream_copy_to_stream($src, $dst) !== false && fclose($dst))
 		{
 			$msg = lang("succesfully uploaded file %1", $filename . ', ' .
 					sprintf('%3.1f MB (%d)', $file['size'] / (1024 * 1024), $file['size'])) .
 				', md5=' . md5_file($file['tmp_name']) . ', sha1=' . sha1_file($file['tmp_name']);
-			$this->log($filename, $msg);
 		}
-		return $msg ?? null;
+		else
+		{
+			$msg = lang('Error uploading your backup!');
+		}
+
+		if (isset($src))
+		{
+			fclose($src);
+		}
+		$this->log($filename, $msg);
+
+		return $msg;
 	}
 
 	/**
diff --git a/setup/lang/egw_de.lang b/setup/lang/egw_de.lang
index de629596ec..f70de9d288 100644
--- a/setup/lang/egw_de.lang
+++ b/setup/lang/egw_de.lang
@@ -324,6 +324,7 @@ error in group-creation !!!	setup	de	Fehler beim Anlegen der Gruppen !!!
 error listing "dn=%1"!	setup	de	Fehler beim Auflisten von "DN=%1"!
 error modifying dn=%1: %2='%3'!	setup	de	Fehler beim Ändern von DN=%1: %2='%3'!
 error searching "dn=%1" for "%2"!	setup	de	Fehler beim Suchen von "DN=%1" nach "%2"!
+error uploading your backup!	setup	de	Fehler beim Hochladen Ihres Backups!
 every	setup	de	Alle
 export has been completed!	setup	de	Export ist abgeschlossen!
 failed to mount backup directory!	setup	de	Konnte Datensicherungsverzeichnis nicht mounten!
diff --git a/setup/lang/egw_en.lang b/setup/lang/egw_en.lang
index 515144d3a9..88c2a2e8d8 100644
--- a/setup/lang/egw_en.lang
+++ b/setup/lang/egw_en.lang
@@ -324,6 +324,7 @@ error in group-creation !!!	setup	en	Error in group creation!
 error listing "dn=%1"!	setup	en	Error listing "DN=%1"!
 error modifying dn=%1: %2='%3'!	setup	en	Error modifying DN=%1: %2='%3'!
 error searching "dn=%1" for "%2"!	setup	en	Error searching "DN=%1" for "%2"!
+error uploading your backup!	setup	en	Error uploading your backup!
 every	setup	en	Every
 export has been completed!	setup	en	Export has been completed!
 failed to mount backup directory!	setup	en	Failed to mount Backup directory!