Sometimes an update changes folder permissions, preventing the game from "opening" the file because Windows has locked it.
The "bigfile000" is exactly what it sounds like—a massive archive. If your drive is at 99% capacity, the game may fail to "unpack" or open the file during the post-update initialization. Ensure you have at least 10-15GB of free space on the drive where the game is installed to allow for temporary cache files. 5. Antivirus Interference unable to open bigfile bigfile000 updated
When you launch the game, click (if available) before the game actually starts. Sometimes an update changes folder permissions