The latest Steam update, which drops support for OS X 10.5 among other things, introduced a bug that causes the program to ask for you to enable universal access for the in-game overlay even if it already was prior to the latest client release.
Here's a fix for that glitch:
1) Make sure Steam is not running and uncheck it from the accessibility preference pane.
2) Close system preferences.
3) Open Terminal and copy/paste the following exactly as you see it, including all quotes:
4) Re-open the accessibility preference pane and make sure that Steam is not listed.
5) Close system preferences, launch Steam, and try to play a game. The warning dialog box about the Steam overlay will pop up again. Use it to go back into system preferences and Steam should have re-appeared. Check the box if it's not already, close system preferences, and you should be good to go.
Here's a fix for that glitch:
1) Make sure Steam is not running and uncheck it from the accessibility preference pane.
2) Close system preferences.
3) Open Terminal and copy/paste the following exactly as you see it, including all quotes:
Code:
sudo sqlite3 /Library/Application\ Support/com.apple.TCC/Tcc.db 'delete from access where client like "%Steam%"'
4) Re-open the accessibility preference pane and make sure that Steam is not listed.
5) Close system preferences, launch Steam, and try to play a game. The warning dialog box about the Steam overlay will pop up again. Use it to go back into system preferences and Steam should have re-appeared. Check the box if it's not already, close system preferences, and you should be good to go.