I was attempting to move files into another workspace with a shorter filepath to troubleshoot some errors, and doing so I followed this thread. It's likely I did something out of order, I'm new to a lot of these things still.
My steps were;
1) Open in Notepad and edit the "C:\Users\xxx\AppData\Local\plastic4\plastic.workspaces" file to have "D:\wkspaces" instead of "C:\Users\XXXX\wkspaces\Project"
2) Create the "D:\wkspaces" workspace on the drive
3) Attempt to open projects, receive "Failed to Launch editor" error on all projects
4) Revert path to the original workspace, attempt to open original projects and receive the same error on the unmoved/unmodified original files and workspace
As the steps show (one and two were probably done out of order), once I managed to bork the new workspace files, the originals now had the same error message associated, when they were fine originally. No changes were made to any of the projects during this. Thanks for your time!