Weird backup problem - file size [update: fixed itself]

Hello all,
I have a rb532a with Mikrotik v3.14
I’m trying to back up the configuration: Files->Backup
Right after I click Backup it creates a backup file, but the size constantly growing,
in about 30 sec whole flash gets filled up and i get “backup failed” message.

I did a search and found similar problem with rb532a with 2.9x OS on it, but no solution.

Any ideas?

try disk checking

Just fixed itself..
Was messing with it all night, couldnt figure it out and left home.
Came back this morning - backs up just fine.
weird