I have a Mac with Yosemite (don't remember the exact version)
I used CleanMyMac today, but it broke something; after using it, I can't open most Apple applications (I can't open App Store, Mail.app, Safari, System Information; it's not working).
Opening the console, I found that the problem seems to be
24/01/15 17:35:36,253 Mail: Unable to load nib file: MainMenu, exiting
24/01/15 17:35:36,255 com.apple.xpc.launchd: (com.apple.mail.7700) Service exited with abnormal code: 1
This happens with almost all Apple applications.
All other apps work fine; Chrome, iTunes, Finder, etc.
I need to find a solution that does not involve bringing the computer to the Apple store; I have a lot of exams in these days and I need my Mac to study.