Subject nbackup : Error assessing database due a missing delta file
Author Jorge Gonçalves

I'm having a problem assessing a database due a missing delta file in our datacenter.
I have tried the flowing commands to repair the database without success. 

nbackup -F
Failure: Database is not in state (2048) to be safely fixed up

nbackup -N
PROBLEM ON "attach database".
I/O error during "open" operation for file "/srv/databases/firebird/ delta"
-Error while trying to open file
-No such file or directory
Failure: Database error

Any ideas how to recover the database ?

ps  : This problem arises sometimes in our datacenter and our IT guys don't now the reason for that. Any idea how to prevent this problem to appear again in the future ?

FB Version :
Server :  Opensuse 13.1