CobianSoft

Perhaps the file is > 2GB and the destination is not NTFS formatted? What is the destination?

Perhaps not a good idea. You will need to approve the elevation everytime on the startup.

What is exactly the problem?

Yes, searching the forum is a great idea.

If you change to 7z compression, do you get the same error?

A parked backup will never be deleted automatically. It's just a protection.

Some people use it to quicky change what to backup.

It can be quite useful just to copy all the tasks to some other computer (just copy the list file to the other machine).

Just park the first backup. It will never be deleted then.