Same. This started suddenly, one day I was fine, the next day the overlay stopped working. I defragmented the game twice, I have uncheck/check the "enable in game community" (in the steam config and in game properties) and I restarted tf2/steam/computer like a million times. I just have no idea what to do, I can't trade in game, I can't go to the store, I can't follow without minimizing, is the most annoying thing ever. Volvo pls, give fix.

Edit: This only happens with tf2, the overlay opens in other games. I actually have tried to open a non-valve game and tf2 at the same time, to see if the "gameoverlay.exe" could work but nothing. v0lvo halp.

FOUND THE SOLUTION

Try to "half-reinstalling" steam. Go to your steam folder. Delete all the files except steam.exe, then you can choose which folders you wanna delete. I deleted the bin folder and config folder. I kept all the other folders. Opened steam.exe, donwloaded stuff again and fixed. Good luck. VOLVO HIRE ME PLS