Freaking error: "Workspace in use or cannot be created, choose a different one"

A few times in the past few weeks when I restarted Flex Builder, I would get this error: "Workspace in use or cannot be created, choose a different one". Nothing online says much about it. Just today I found the solution to this. Basically if the java VM is still running (which is probably locking up the folder), you would get that message. Simply kill the process javaw.exe, you are good to go.