Hello!
I have a problem - when I am in-game I can't open the overlay (Shift+Tab) I did nothing to the options. Also I have enabled Overlay in the steam settings and in css properties. In other games I can open it but not in CSS. Can you help me?
I tried to change binds for the overlay but still can't open.

Did you try asking in the Steampowered forums? Wouldn't it be the best place to ask for support for Steam games and their problems?

If you go to properties and then general, is the enable steam community in game checked?

I have this problem with Darksouls. When you start the game do you see the little message that steam shows you everytime you start a game?

I posted the problem on the community hub of the game, steamgifts forum and here. I am gonna post there :) Yes, its checked. No, even if I click on achievements (usually its open the overlay) nothing happen.

Can this help you out?
https://support.steampowered.com/kb_article.php?ref=9394-YOFV-0014

Already saw this, but I will read again.

Then I don't know the solution. I posted the same questions a month ago to fix Darksouls :( Good luck!

Thank anyway, good luck to you, did you found solution or?

Last attempt to fix :p
This link seems interesting to read as well.
http://forums.steampowered.com/forums/showpost.php?p=34074154&postcount=17

Sadly no solution. Many people are in the same situation and there is no fix apparently :(

Ah, look like wont be fixed soon :(
I am sad, this is my favourite game ,but if I find solution I will post

Thank you for the support, guys.
The update of the game fix this problem.