I have a imac from mid 2011 with 8 GB Memory & 3 TB Hard Drive running Mac OS X 10.10.5. Trying to get into a MAC Book pro I previously thought I had no access to, due to the grey screen of death. You need to set the type of the format for Mac OS Extended (Journaled). Select the unmounted Macintosh HD from the left-hand panel. 3. 1. iMac 2020, Retina 5K, 27-inch). 5. Restart Mac, press and hold Command + R keys down until a menu appears on the screen. I need the apps/info on it ,and do have a back up or I do not have a disks for Rosetta stone, Office 2013, full adobe which was installed. So I went to Mac OS utilities and went to disk and accidentally deleted my 3TB hard drive. Is your Mac start-up disk is failing or you suspect the MacOS disk is corrupt? Rebooted it today, got to an enter password to unlock the hard drive screen. locked hard drive can't reinstall Lion OSX. Question: Q: how can I reset my "unlock the disk Macintosh HD"? Another possible reason for "macOS Big Sur Cannot Be Installed On This Computer" is that macOS 11 simply is not compatible with your Mac (e.g. Assuming you don't need any data off the drive, try opening Disk Utility form the recovery screen and go to the erase tab then format Macintosh HD to Mac OS Extended (Journaled). Step 8: Run the following command: 'Volumes/Image Volume/boot.sh' Step 9: Follow the wizard to recover lost data from the internal hard drive. I think it is 2014 model btw. You already tried to partition the disk multiple times but it keeps erroring with the Error: -61. Then I wanted to get a fresh copy of Yosemite and it is asking me to choose a disk, there is no disk to choose. So I tried to delete the HD and reinstall. Step 11: Select Disk … In the Menu, choose ‘Disk Utility, next click the button ‘’ In the Utility menu, choose your Startup volume which in most cases is called Macintosh HD. Then quit Disk Util and try the install. 2. 4. If successful, the key will unlock the encrypted startup disk and take you back to the login screen. In this case you can try: How to fix: If you can't upgrade from macOS 10.15 Catalina to Big Sur, you need first update to 10.15.6 before installing macOS Big Sur. I forgot my password, since I changed it in previous rebooting attempts. Solution 3: Fix Macintosh HD not mounted by Terminal. Had a strange issue with my Mac where the password box was not popping up and I couldn't log-in. Are you worried about your files on the Mac storage drive? Click First Aid on the top of the window and wait while it verifying and repairing errors. Shows utility disk needs to be repaired, but computer cant repair it. Step 10: Restart the Mac, press and hold Command + R keys immediately to get into macOS Recovery mode. Step 7: Wait for your Mac to boot up, open "Terminal" application from "Utilities" drop-down menu. I think I also have restored the 1.51 Gb OSX base system back on and it no longer appears as an external disk… If that won't work, run the command below in Terminal and tell me what it says. Since yesterday my mac will boot and then shut down. I believe you followed the official guides and you tried to factory reset your Mac and you find yourself in this situation: the disk is locked and you cannot select it for re-installation . Go to Disk Utility --> Erase Disk --> Select Erase with Journaling. Both recovery disk and Macintosh disk are locked and I am unable to just re-install. Boot your Mac into Recovery Mode. @danj also suggested in this solution to create a separate bootable thumb drive to reinstall OS X from, erase the disk using Disk Utility, and that apparently solve the issue. If Disk Utility stopped repairing Macintosh HD in macOS, you can then try to fix it with Terminal.