Thanks Faisal!!
But why the lines numbers are deleted is not known!!
I don't know, really. I'm using the same version of C 2 and I haven't had the problem.
There is one bug that we know that perhaps have been fixed in the latest service pack. Say you have a C 2 file opened in Input Processor. And then you open a different file from the Input Processor. The previous file will be archived in .C 2, but the .c2db will be left out of the archive. And if the user isn't aware of it and move only the C 2 file to a different location, the line number information will be lost when the user opens the file from the new location. Perhaps that's what happened to you. Other than that, I have no idea. Try updating to the latest build as Richard suggested.