If you are using an external drive, ensure it is plugged into a USB 3.0 port, as slower speeds can cause timeout errors when opening large files. Reinstall the Game

Antivirus software loves to block bigfile.000 because the game constantly reads large chunks of data from it, resembling suspicious behavior.

How to FIX Rise of the Tomb Raider Not Launching/Not Starting

: In Steam , right-click the game > Properties > Installed Files > Verify integrity of game files .