If you haven't already tried it, please reference this sticky topic first before trying this: Missing Textures, Models, or Map This topic assumes you've already tried the above and it isn't fixing your crashing issues. Here is where we explain the steps you will need to take in order to repair your Garry's Mod Installation, as it is assumed that somehow it got corrupted. This happens absurdly often and it can be caused by something as simple as joining YukiTheater and not initializing correctly client-side. The first step is to do the classic Verification of Game Cache. To do this: Open Steam (make sure Garry's Mod is closed) --> Go to Library --> Right click on Garry's Mod --> Click Properties in the drop-down menu --> Click the Local Files tab --> Click Verify Integrity of Game Cache Try rejoining the server after cache verification completes. If it crashes again, you're going to have to do a complete wipe and re-installation of Garry's Mod. Warning: The Following Steps WILL delete all data in your Garry's Mod Installation! Backup your Important Files first, if you have any (Instructions to back up commonly important files is below)! To Back up your Addons and Local Data: Go to SteamApps/common/GarrysMod/garrysmod/ (SteamApps will most likely be located in C:\Program Files (x86)\Steam or C:\Program Files\Steam, unless you installed Steam to a different drive) --> Copy the addons and data folders to somewhere else. The easiest place would probably be your Desktop. To uninstall: Open Steam (make sure Garry's Mod is closed) --> Go to Library --> Right click on Garry's Mod --> Click Delete Local Content in the drop-down menu --> Click DELETE to confirm --> Wait for Garry's Mod to uninstall from Steam and once the game has a gray name indicating that it is finished uninstalling --> Go to SteamApps/common/ and delete the GarrysMod folder in it to finish uninstalling Now, to re-install: Open Steam --> Go to Library --> Click on Garry's Mod --> Click Install --> Once Garry's Mod is downloaded and installed and the Play button is usable, copy the previously backed up Addons and Local Data back to SteamApps/common/GarrysMod/garrysmod/ (overwrite the addons and data folders with your backups) Now launch Garry's Mod and your problems should be fixed! If they aren't however, reply to this thread and I will try to assist you.