Chosen Solution
I turned on my MacBook Pro for the first time since about 4 years. Instead of going to the account screen, the Mac showed a choose-your-language screen and then the OS X Utility. It seems that there is no data on the hard drive (except for ~300MB in Other) according to Disk Utility. I restarted the Mac with the Startup Option by pressing the option key and the only available disk is called “Recovery-10.11.4”. Is the data actually gone? Is it possible to recover the data and /or account? Thank you for your help!
Boot up from your original system installation disk or and external drive. Run Disk Utilities and see if you can repair it first. This failing we can go to more Herculean methods.
