Luckily, we do have quite a few tricks and tools up our sleeves to get this handled properly fixing the system making sure maximum possible data recovery. In this post, I will be sharing three possible solutions to get this issue resolved.
The most easiest method you should try first is to use the fsck command-line tool from Mac OS X recovery to check and repair the consistency of the corrupted file system.
1.- Boot into Mac Recovery by keeping Option/Alt key pressed at boot.
This is a Guest post by Devin Sukhu. Thank you!