After doing a bit of research here is the short answer:
If you updated to a new WordPress version and were welcomed with error messages, unaccessible admin interface and isn’t worth my time debugging this feelings, these quick steps are for you.
Returning WordPress to a previous version is safe (from a functional perspective) most of the time. You should try to update again once non-compatible plugins get fixed.
Database changes between minor WordPress versions are few, but if you don’t have any kind of disaster recovery plan in place, you’ll be in a safer position if you backup it before restoring WordPress.
Did you apply Trim Enabler patch? Did a SMC/PRAM/NVRAM reset turned your mac unbootable?
If you are stuck at boot you can try to disable trim via Recovery Partition or a bootable OSX Installation USB drive.
Boot into Recovery ( CMD + R ) and open Terminal utility. Type as follows: