Error Updating Garrys Mod (Unknown Error)

I have just yesterday tried to launch Garrys mod from steam, however, when I try to launch it says that it needs to update but when i do, it gives me this error message a few seconds into the update. When i go to my library in steam, it says that gmod is updating but paused. I have tried to ‘Verify Integrity of Files’ Or whatever it is, but wont let me because it is “still updating”. The only way that i can play is to launch the game from hl2.exe in my steamapps folder, then it works fine and gmod can connect with steam and everything normal…
Im running Win7 if that helps ?

I would put on some screenshots, but idk how :3
Is this an error with steam of Gmod?
Thanks, Ethan

If you press the print screen button on your keyboard it copies a screenshot. Then just paste it in paint and save and upload to an image hosting website. Does this not happen with any other games?

Try deleting the local content and reinstalling.

Ho do you do that? I will post images if you want, i dont know which to do tho :3

Right click on Garry’s Mod in Steam and click “Delete Local content”