We may need to take this to FReepmail to keep from boring everyone.
The only was to lose a WU is to delete the files. Therefore, do not empty your trash can.
Is the original directory still where is used to be? Is there anything in it? If so, a reboot will cure most ills.
If the directory is empty or if it has been moved, then we get to ask and answer a lot of questions to save the WU. It can be saved if you want.
Or just forget the old WU like an old boyfriend, install the two new instances and commence to folding anew. (I've been dealing with a teenage daughter)
Too late.
Consider him forgotten.