error 2262 No access to backup set __scrip_name, error -2262 (catalog file in use by another device)

[retroterror641]

I have a script that transfers snapshots of a backup catalog once a week to an external HD.

Unfortunately, the process breaks with the message "No access to backup set __scrip_name, error -2262 (catalog file in use by another device)". (text translated from German to English) aborts.

If I insert single sub catalogs from the catalog into the script, it works, but only not with these one.

 

I deactivated everything I could, restarted the server, but it always hangs on this one particular file.