I run eclipse on Ubuntu 11.10. I originally created a project in folder foo. I subsequently deleted that project to re-organise folders and I now want to create a new project in folder foo/bar but Eclipse won't let me because it says the the new directory is a sub-directory of an existing project.
How can I force Eclipse to forget about the original project so that I can create the new one?
In general, the deleting the project from the "/.metadata/.plugins/org.eclipse.core.resources/.projects" should work, but if you're using 'working sets', you might have the problem I had once, which is basically have a 'ghost' project in your workspace that you can't delete because it says "this project doesn't exist anymore".
If this is your problem, try to delete an entry for your 'ghost project' in the file:
"/.metadata/.plugins/org.eclipse.ui.workbench/workingsets.xml" (on MacOS).