I have an old database running on Windows 7 PC with Firebird 1.5, working just fine for years (from 2005.).

Currently, FDB file is little larger than 700MB.

Now, I decided to update to FB3. Nothing simpler, I thought. Just gbak backup with FB1.5 and restore on FB3.

But, I have an issue which I cannot understand. My gbak doesn't report any error or failure (log file empty), but when run with -verbose, I just get:

gbak: 160000 records written

gbak: 180000 records written

gbak: 200000 records written

gbak: 220000 records written

gbak: 240000 records written

gbak: 260000 records written

gbak: 280000 records wri

and it breaks - brings me back to terminal. 

FBK file created is cca 200 MB, but cannot be restored - gbak restore (also on FB1.5, just checking the backup) asks for another volume etc. So I believe backup is broken.

What would be the path to successfull backup or at least finding the reason why it doesn't work as expected?

The app using the database works fine, there are no errors related to DB...