If you cannot boot into VRChat or VRChat gets stuck on loading there are a few things you can try:
- You can re-run the installer to re-install VRChat
- In your '%Userprofile%/AppData/LocalLow/VRChat/vrchat' folder there is a file called parse.settings. Try to rename this to parse.settings.bak and relaunch VRChat.
- If you still cannot get into VRChat try to rename the entire '%Userprofile%/AppData/LocalLow/VRChat' folder to 'VRChat_bak' and reinstall VRChat. Then try to load VRChat.