DVT VHDL IDE User Guide
Rev. 19.1.32, 20 September 2019
Problem: I'm unable to select an existing workspace after my eclipse program that was accessing it was not shutdown properly. I get a "Workspace in Use" error when there are clearly no other eclipse instances running on my machine.
Solution: If you are sure there is no eclipse looking at your workspace (not even another user), then you must remove the lock file located in the workspace at path_to_workspace/.metadata/.lock.
On Windows, if you cannot delete this file (because another process is using it), then close all eclipse IDE sessions, do Control-Alt-Delete to bring up Windows Task Manager, select Processes page, and delete javaw.exe.