Hi everyone ! I’ve some fix for you ! This worked for me and my friends !
-FOR the hl2.exe crash when joining server -> just delete every .dll in garrysmod/lua/includes/modules (I think it’s because they don’t work with the newest update)
-FOR the settings reset when you quit Garry’s Mod : It’s worked for my ATI 4870 HD… Just update with the newest version of your graphics drivers !
If you have “Invalid Steam Key Size” it’s because the server is not up to date !
*Sorry for my poor English, I’m a french dude who want to help.
Post any others FIX here !
Bye ! Hope this helped you !