This thread is for our known solutions that may work for other people's problems, and please give credit to the solution giver. Also, if you post a solution that was found in someone else's question/thread, please credit them too.
These are mine (from my questions):
Portal2 Portal 2 mod crashing on other systems: Delete the bin folder inside of the sourcemod folder (Solution given by CamBen)
Portal2 Models Missing texture or Invisible: Make sure the paths are correct (Solution given by Crawfish)
Portal2 No 'Paint in Map' in Map Properties: Turn off smartedit and add the keyvalue 'paintinmap' (without quotes) and set it to 1. (Soloution given by TeamSpen210)
