Flex: Workspace in use or cannot be created

I have seen this annoying message more often in Flex Builder 3. It looks like the locks are not properly released when you quit Flex Builder.

If you get this error, You have 2 options

Option 1

1. Go to Task Manager
2. Kill FlexBuilder.exe
3. Kill Javaaw.exe

Option 2
Restart your pc

Either option will resolve this for you.