Quietly ignore files in use when doing a backup

I've noticed that when making an Opus config backup, if a file involved is open/in use/locked, the backup fails.

Could you add an option to the Backup dialog and the relevant internal commands so that if a file inside the User Data folder is in use during the backup, it is simply and quietly skipped instead of stopping the entire operation? Or is there already an option for this?

We'll add a way to do that in the next update.