>>I hate this. My project can be fine, but then suddenly the source is out of date and I can't run trace on the code. I have the same paths, etc. setup, but then suddenly it will come up with this. Why?!
>
>Try to re-build the project with the re-compile everything checked.
>
>Not an answer on "why" part, but more "how" to fix it.

Been there, done that. No fix.