Originally posted by Ready or Not Troubleshooting Steps:

1) Verify the game files (right click on Steam > Properties > Local files > Verify integrity)
2) If you have any mods, remove them and verify the game files (delete the .pak folder if necessary)
a) Navigate to C:/Users/Public/mod.io/3791/mods and delete the mods there, then
b) Navigate to %appdata% > local > ReadyorNot > Saved > Paks, delete the folder/mods inside there
c) Navigate to steamapps\common\Ready Or Not\ReadyOrNot\Content\Paks, delete the mods there.

3) Update your drivers and windows (even to optional build, or even manual install)
4) Temporarily disable anti-viruses and test if issue persists
5) If all else fails, do a clean install below:
- Uninstall Ready or Not on Steam
- Navigate to Steam > Steamapps > Common > Delete "ReadyorNot"
- Navigate to %appdata% > local (%appdata% by default is roaming) > delete the "ReadyorNot" folder
- Reinstall Ready or Not