Its relatively quick/easy to recreate a user's profile and only impacts the user's profile on their machine - things like default server, username, and password, if you permit saving - not their data.
Sign out, and exit the client. (Double check that no MyWorkDrive icon appears running in the systray.)
Browse to and delete any files/folders in "C:\Users\%username%\AppData\Local\MyWorkDrive". There should be user profile folder(s) there which start with "MappedDrive.Client.Window" proceeded by a GUID.
Run the client again and it will re-create the profile and prompt for the server login information again. The user will need the server address to login again as the login page will start blank.
Most issues can be resolved by ensuring that the user has the proper permission to their C:\Users\%username%\AppData\Local\MyWorkDrive\*.* folders and Antivirus Exclusions are in place.