Installing a new version of the Mac OS is generally a fairly pain-free process; this trend continues with macOS Catalina. Click on the Apply button, then wait for the Done button to activate and click on it. If the Macintosh HD won't mount, and your Mac still cannot recognize the Mac internal hard drive, the final chance is to factory reset the Mac - format the Macintosh HD and reinstall macOS on it. MacOS will now be installed on your hard drive from the bootable installer. Backup your Mac with Time Machine . A panel will drop down. I had previously completely backed up my Catalina system to an external SSD, and as I had to work today I gave up on Big Sur for now. Then quit Disk Util and try the install. Try installing the update again. 1. The issue is likely fixable, but it may not be the simplest fix in all cases. Go to the Apple menu, and choose About This Mac to check the Mac model, and the following Mac models are supported: Related. But as you know, reformatting will erase all the data stored on the Macintosh HD. The ‌macOS Catalina‌ installation takes some time so don't restart ahead of when the setup screen pops up, but based on a multitude of reports, resetting in this way if it gets stuck … When Disk Utility loads select the volume (indented entry, usually Macintosh HD) from the Device list. Solution 7: Erase the unmountable Macintosh HD and reinstall macOS. If your Mac encounters difficulties when downloading or installing the latest release, don’t panic! Install Mac OS on external drive: disk locked. If that won't work, run the command below in Terminal and tell me what it says. Click on the First Aid tab in the toolbar and wait for the Done button to activate. Reinstalling Mac OSX Lion on Locked Disk. The … I had left my 16 inch MBP overnight, still stuck at 100%. But, I see that instead of Macintosh HD and Data volumes, I have one volume, called Update. Then restart the Mac. Connect the external hard drive to the Mac, and run Time Machine to make a backup before the update. Check your Mac model . 3. Click on the Erase icon in Disk Utility's main window. Select Restart from the Apple menu. To avoid losing any data during the macOS update process. Either way, here are the troubleshooting steps you should take to fix a Mac that won’t boot. Click on it, then quit Disk Utility. After the Mac reboots, try to install the macOS Catalina, Mojave, High Sierra again. Most of the time, macOS should be able to resolve these issues gracefully, but occasionally it may cause your Mac to lock up halfway through the update. Problems reinstalling OS X Mavericks on Macbook Pro (hard drive displays “locked” and I get “live file system repair is not supported” when repairing) 2. Then select the indented (usually, Macintosh HD) volume entry from the side list. b. There could be a variety of problems causing a Mac’s boot process to fail or for the boot process to get “stuck” on the loading bar. I clicked Install, and then nothing happens. Select Macintosh HD as the installation disk, when presented, and click Install. I get as far as the install screen that shows Catalina will be installed in disk “Macintosh HD” and the back / install. It’s tough to say. If the installation get stuck when you try to update the Mac from Mac App Store, you may download macOS software from Apple website, which is the Combo updater which includes all the files required to update the macOS. In this article, we share seven fixes that can fix your frozen Mac and get it back on track. Keep getting stuck on 'Installing on "Macintosh HD"' and 'About 24 minutes remaining' for an hour or two, then it comes up with something like 'It was not possible to install El Capitan', which I'm fully aware; however it doesn't seem to give me any obvious option to revert to OS X 10.6.8. I waited a few hours and still nothing has happened. 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). 1. a. Set the Format type to Mac OS Extended (Journaled.)