Mysteriously got the following exception when trying to build an Eclipse project:
“resource is out of sync with the file system”
Although I can’t be sure, I think I may have deleted a file outside of Eclipse. To fix the problem, right click the project or edited resource and select “Refresh”. Alternatively, you can enable auto-refresh by going to Window->Preferences menu, then in the Preferences dialog box, select General->Workspace. Check the “Refresh automatically” box.
This is for Eclipse 3.3. I don’t know about other versions.
When we have so many project out of sync, this would really help as it did to me.