Thanks for following up.
Can you confirm that you've followed the steps described in this article: https://support.rstudio.com/hc/en-us/articles/200534577-Resetting-RStudio-s-State; especially around removing the folders at:
%appdata%\RStudio
%localappdata%\RStudio-Desktop
If that still doesn't work, then it might also be worth trying to enable Windows Minidumps, just in case RStudio or the rsession is crashing during launch. Instructions follow:
You can try creating a Windows Minidump. First, you need to enable Minidumps explicitly. Microsoft provides explicit instructions at https://docs.microsoft.com/en-us/windows/desktop/wer/collecting-user-mode-dumps. If you'd like to automatically enable user-mode dumps, you can also try importing the following registry file:
Restart your computer afterwards to ensure the registry updates take effect.
Next, try to launch RStudio. If we're lucky, the crash dump will be written to a folder at:
C:\Users\%USERNAME%\AppData\Local\CrashDumps
replacing %USERNAME% with your Windows username as appropriate. Note that AppData is a hidden folder, so if you're trying to navigate to it in the Windows explorer you'll need to ensure hidden files and directories are made visible.
Then, within the folder, you should find files of the form:
*.exe.<id>.dmp
Depending on what application has crashed, you should see dumps for either rstudio.exe or rsession.exe. If the file is large, you might consider uploading it to a cloud storage provider (DropBox, Google Drive, Windows OneDrive) and sharing a link to that file for us to examine.
If you'd like to later disable Windows minidumps, you can run the following registry file: