My daughter's 2012 MBP would not load the OS (Lion I believe). She took it the the Apple store and they told her it was a failing hard drive but her AppleCare had just expired. I was able to boot the drive into recovery mode, but the main volume was not recognized. I tried to target boot with an iMac but the drive would not mount.
I put a new SSD in the MBP and it runs great. I put the old drive in a USB case and tried to mount it on an iMac, I was prompted for the password, entered it, but the drive wouldn't mount.
At this point I'm trying to see what my options are for data recovery. I thought I might try something myself before sending it out, but don't understand how programs like Data Rescue & EaseUs would work when the drive won't even mount?