Was the Mail App ever moved out of the Application folder?
After installing Security Update 2012-004, you may not be able to open Mail. This alert may appear:
"You can't use this version of Mail with this version of Mac OS X. You tried to open Mail version 4.5 (1084/1085). It can’t be used on this version of Mac OS X. Try opening the version of Mail located in the Applications folder on your computer."
This can happen if the Mail app was moved from Applications to another location, such as the desktop, before installing the Security Update.
- Hold down the Option (⌥) key and choose Apple () menu > System Profiler… to open System Profiler.
- Click "Applications" in the "Software" section. Note: The spinning gear in the top middle indicates a search in progress. Once completed, sort by application name and look for "Mail" to see all copies.
- Make sure Mail v4.6 is located in the Applications folder—move it back there if it is not.
- After moving Mail back to Applications, reinstall the Mac OS X Update v10.6.8 Combo v1.1.
- Reinstall Security Update 2012-004.