Got this to work How to install without misteamprep: Extract Patch Open the base content folder extract each GCF file in the Patch folder (overwrite if asked to) After you are done make a shortcut of hl2.exe go to proprieties at the target type: -steam -garrysmod -appid 4001 And rename the shortcut Garry's mod 11 EXACTLY LIKE THAT OR IT WONT WORK!