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".
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.