It happened to me when I was creating a test chamber. The computer got overheated and closed down. After that I got this crash. I was clicking to "Create Test Chambers" but it was closing directly without any errors. I switched my account and it worked. I tried to get help from steam support but it was no use. Than they told me to check guides like this one. I couldn't find anything ether.

I fixed it without knowing. I was low on storage so i was opening some space. Usually i delete steam games normally, but i saw that the games that i didn't downloaded where eating up HUGE space! I started to delete games from This PC/Local Disc (C:)/ steam / steamapps / common. I deleted Portal 2 too. When i was bored I just wanted to play Portal 2. When I clicked to Create Test Chambers, IT WORKED!

Head to This PC








Than go to Local Disc (C:)







Than Click to Program Files (x86)















Than find and click to Steam


























Than go to steamapps


















Click to common,



















And then delete Portal 2 folder!



























You are done! Now go continue making sick game chambers!