New job error - file size in destination is different than the size stored in catalog

[Alexandro]

Dear Support Team,

I am getting the following error in a backup job: file size in destination is different than the size stored in catalog.
This is a new job, and I cannot run an independent test for that backup by pressing the Test (F9) button.

I am trying to solve this problem by e-mail with support for more than two weeks, but are always asking me the same questions, with no solution.

What can I do to solve this?

Thanks in advance!
Alexandro.