Please do a full clean re-install:
- move any valued save games elsewhere
- "uninstall" in Steam-Vic3
- manually delete both the Steam/SteamApps/common/Vic3 AND Documents/Paradox Interactive/Vic3 folders
- re-install game in Steam, run a Steam Verify when done.
- add Victoria3.exe to the exceptions list of your antivirus app; ESPECIALLY if you have Windows Defender, add it to the Ransomware "Apps Allowed Through" list.
- start the game with no mods active and test
In particular make sure there are no files or folders left under either the Steam Vic3 or Documents Vic3 locations, before installing again.
If those don't help:
DXDIAG is a program you run from the Windows search box on the task bar. After running it will open a window and start collecting info with a progress bar in the lower-left corner. When it completes click the 'save all information' button and save it to a file then attach that file here.
Please attach here your Documents/Paradox Interactive/Vic3/pdx_settings.json .
From your Documents/Paradox Interactive/Vic3/logs/ folder, attach here system.log , error.log , exceptions.log
