That's really very little information :-). Which program is it? What is the warning?
Its a custom program.
We just migrate from 11i to R12, but till last week it was working fine in R12.
All of a sudden this week its completing with warning though the program works fine and there is no error information in log file.
On which step ?
Any description after taht ? Any details ?
So it's a custom program. So the first steps are to check whether any conditions in your code set retcode to '1'. If not then you need to start checking it's not the output post processor that's caused the problem and so on.
However simply posting "my custom program finished with a warning, what might it be?" isn't going to get your problem solved very quickly.
These issues are generic post upgrade.
Post the messages from logfile : (Concurrent --> requests --> Search --> view log or from $APPLCSF/$APPLOG)
Troubleshooting is not possible unless you post the exact message in logfile.
Then change your custom program and put some log messages in it, so you know what is happening and where it stops with warning?