how to delete non-exist project from eclipse

none of the above worked for me but this solution worked (was really a ghost project)

1. Shut down Eclipse
2. Open <workspace>/.metadata/.plugins/org.eclipse.ui.workbench/workingsets.xml
3. Find the faulty tag and remove it
4. Start Eclipse

You may try this :

• Close your workspace :
• Delete the dir client-target from <workspaceDir>\.metadata\.plugins\org.eclipse.core.resources\.projects
• Open your workspace

And should be good

VinyJones answer did not work for me, since there was no corresponding metadata for the non-existant project. The solution for me was to drag the non-existing project to an other working set. After dragging it disappeared.