System Formatter Failed While Erasing External Hard Drive Mac I have been trying to erase my external Hard Drive "My Passport", however there was a problem and then the Hard Drive disappeared from the Desktop and could't be found. Only Disk Utility would see it but it would't mount it. I tried erasing it and partitioning it, however nothing helped and i'd always get this error: "System Formatter Failed".

I found a few links that worked on previous version of OS X, eg. Link 1, or Link 2. None of those worked, I always would get the error message and could never mount the drive.
The solution that works on both OS 10.11 El Capitan and on OS 10.10 Yosemite is:


Open up Disk Utility
Select the actual drive, which is the lower part that will most likely be greyed out:
Then go to Erase
Select MAC OS EXTENDED (Journaled, Encrypted) It's important to select Encrypted
Then enter a password and wait.(It will run without a problem )
Then you can again erase and take the password down and use your drive again.