Do you have the Steam version of CMS or did you have the 'Epic' version installed at some point? If you previously had the 'Epic' version of base game installed, you'll end up with some erroneous Windows Registry values for CMS. If that were the case, you'd want to completely uninstall CMS, restart the PC, and then do a Reg Cleaner to remove all registry entries for CMS. First make a backup of your 'Profile0' folder (your game save) and any other 'ProfileXX' folders if you have multiple saves going. Set those aside. Cuz, after you uninstalled, you should have gone through PC and deleted all CMS related folders off the PC... to include one's left in your user's hidden system folder 'AppData.' Once you've completely cleaned the PC of CMS and the Registry, restart again. Now do a clean install of the game. Do the 'Verify files' from steam's game properties. Also, disable that 'Cloud Sync' cuz it'll likely mess up your saves. Once up and running, you can copy your 'profile(s)' back to your user folder. I'd first test to see if Workshop mods will install. No point bothering with the save till you know you have it working.