This is a comment on Backup & restore, posted by WikiAdmin at 07.03.2023 16:18

View source for Re: Backup & restore

The restore module does the following check before it throws that error message:
$dir = UPLOAD_BACKUP_DIR . '/';

if (!is_executable($dir))

So I guess you must make the folder executable for the user or usergroup you're in. Somehow this isn't the case yet. Please check your file permissions again.

It seems there might be an issue unter Windows.

Can't remember having issue with that, however I work mainly in a Unix environment.