Please fix the FICO Workbench uninstaller so that the user settings in the AppData folder (e.g. C:\Users\MarvinW\AppData\Local\xpress-workbench) are also removed.
I observed the issue when I had to roll-back to an earlier version of Xpress and Workbench, and then Workbench was unable to open. It was incredibly difficult to troubleshoot as Workbench didn't display any error; it just didn't open. I had to go into the debug log (e.g. C:\xpressmp\workbench\debug.log) to find this cryptic error:
[0523/150525.261:ERROR:process_info.cc(625)] range at 0xfffd3000, size 0x230 fully unreadable
[0523/150525.269:ERROR:process_info.cc(625)] range at 0xffe49000, size 0xf84 fully unreadable
[0523/150525.343:ERROR:http_transport_win.cc(127)] WinHttpCrackUrl: The URL does not use a recognized protocol (0x2ee6)
which I then found suggestions online that it this error could be from bad AppData, and fixable by deleting Xpress Workbench's AppData folder.