Left 4 Dead 2 BEX Crash Problems
Left 4 Dead 2 generally has good gameplay, but errors and bugs do appear in the game from time to time. Some of these errors can cause Left 4 Dead 2 BEX crash events, meaning that the problem type is listed only as "BEX." These errors can be frustrating, but they are usually fixable.
Left 4 Dead 2 BEX Crashes
Though the original Left 4 Dead was the winner of multiple awards and a fan favorite, it was not without its bugs and errors. Its sequel adds more of the gameplay and zombie hordes that players love, but unfortunately it has its occasional problems as well. Left 4 Dead 2 BEX crashes are some of the most frustrating of these errors, causing the game to crash to the desktop without giving the player much in the way of information on what went wrong. The typical BEX error report lists the problem event name simply as "BEX", and aside from listing Left 4 Dead 2 as the program that crashed there is little aside from error codes to be found.
What Is a BEX Error?
The key to understanding what's going on when a Left 4 Dead 2 BEX crash occurs is to figure out exactly what a BEX error is in the first place. "BEX" stands for "Buffer Overflow Exception", which is an error in memory allocation that occurs when a program attempts to make use of system memory that is not available to it. The BEX buffer is part of the Windows data execution prevention (DEP) system which is designed to prevent programs from running malicious code. Though most users assume that this means that there is a problem with their operating system or that the DEP system is malfunctioning, in most cases BEX errors are caused by problems within the program that crashed. If Left 4 Dead 2 BEX crashes keep occurring with your game then it's likely that some of the game files have become corrupted and your game is attempting to run outside of its normal parameters. Fortunately, file corruption that can lead to BEX errors is usually easy to fix.
Fixing the Left 4 Dead 2 BEX Crash
The first thing that you should do when you experience a Left 4 Dead 2 BEX crash is to see if you can replicate the problem. One crash doesn't necessarily mean that you have a major problem with your game; it's possible that the crash was a result of a temporary problem that won't repeat itself. If your game crashes again with another BEX error, however, then you're going to have to do something to fix it.
Uninstall any game mods and custom maps that you may have running in your game. This includes small mods such as textures and scripting mods as well. If there is a problem within the mod files it may be causing your game to exceed its memory buffer, leading to your BEX crashing problems. Try playing without the mods for a while to see if the problem goes away. If it does, re-download any mods that you had previously used before reinstalling them since the problem may have been caused by a file corruption during the mod download.
If you didn't have any mods installed or you still have BEX errors while playing, open Steam and right-click the Library entry for Left 4 Dead 2. Select the "Delete Local Content..." option from the menu that opens, clicking the "Delete" button to remove all of the local files saved to your computer. Don't worry about your saved games and achievements; Left 4 Dead 2 uses the Steam Cloud, so all of your progress is safe. Once you have removed all of the local files, re-download the game to ensure that you have uncorrupted files which won't cause future BEX crashes.