Buy the game Monochroma some time ago and no one achievement has earned until I passed it. Already trying to get help in steam forum, but nothing. Maybe anyone have this kind of problem on mac platform with steam games? Thanks for watching!
Steam uses OS X's Accessibility API for the Steam Overlay (Shift+Tab screen) and to communicate between the game and Steam.app. You probably enabled it when you installed Steam. Unfortunately, every time you update Steam (this is a bug in OS X) you must uncheck and re-check the box in System Preferences. If you're having this issue on your Mac but not Windows, that's the reason.
Just go to System Preferences > Security & Privacy > Privacy > Accessibility, unlock using the icon in the bottom left, and uncheck and re-check Steam.
- Make sure all your OSX updates are installed
- Follow 0942v8653's suggestion and toggle off the Accessibility API for steam
- Completely remove Steam
- Reinstall Steam
- Toggle back on the Accessibility API
There may well be better ways, but this is my hip-shot guess on this one.
You need to give Steam access in the accessibility settings and then you may need to restart Steam and or reinstall. I have had a similar issue where Steam does not detect that it has been given permission in the settings and it was fixed by a quick reinstallation of Steam.