Upgrade sticks with 1 minute remaining. Turning imac off, then on again leads to same problem. Think there is not enough space to complete; I assumed possibly wrongly, that lack of space would be mentioned before the upgrade started! How can I get back in to change this?
iPhone 7, iOS 15
Try booting into Safe Mode.
If that also does not work, then boot into Recovery Mode. Launch Disk Utility and select the internal drive's Data volume. See what the "Free" space value is reported. There should be at least 35GB+ of Free space listed....more is better since it is hard to say how much the installer may need, plus it is hard to say what services you may have running in macOS that may be eating up storage space. By default the Monterey installer needs at least 35GB+ of Free space (or about 50GB+ if installing from Recovery Mode or USB stick).
You don't mention the exact model Mac, but perhaps the internal hard drive is failing. An OS install stresses a hard drive much more than regular use and utilizes portions of the drive that may rarely be used so it is not uncommon to encounter a drive failure during an OS install/upgrade. You can try running the Apple Diagnostics to see if any hardware issues are detected, but unfortunately the diagnostics don't usually detect problems...never hurts to try though.
Edit: Also disconnect all external devices in case one of them is causing a problem.
Try booting into Safe Mode.
If that also does not work, then boot into Recovery Mode. Launch Disk Utility and select the internal drive's Data volume. See what the "Free" space value is reported. There should be at least 35GB+ of Free space listed....more is better since it is hard to say how much the installer may need, plus it is hard to say what services you may have running in macOS that may be eating up storage space. By default the Monterey installer needs at least 35GB+ of Free space (or about 50GB+ if installing from Recovery Mode or USB stick).
You don't mention the exact model Mac, but perhaps the internal hard drive is failing. An OS install stresses a hard drive much more than regular use and utilizes portions of the drive that may rarely be used so it is not uncommon to encounter a drive failure during an OS install/upgrade. You can try running the Apple Diagnostics to see if any hardware issues are detected, but unfortunately the diagnostics don't usually detect problems...never hurts to try though.
Edit: Also disconnect all external devices in case one of them is causing a problem.
It'll reboot upto 7 times & appear to be doing nothing for long stretches, plus I've seen "Less than a Minute remaining" take over an hour.
Go have lunch, dinner, & take in a movie! ;)
If you are operating with less than 256 GB SSD storage, you are running on too little space.
If you need photos or videos, you'll want more.
An external USB hard drive is probably one way to at least access the files, and at least start with enough space to clear up enough internal space to allow for installation. I don't recommend having less than 15% free + 24 GB.
Thanks for this. However, I am old and not at all good technically! So could you please tell me what are safe mode, recovery mode, and launch disk utility? And where do I find them when the screen stays blank while trying to upgrade?
My Mac is MacOS Mojave version 10.14.6 from 2017. I have tried all 3 solutions mentioned in a previous reply, but none of them will work when, on turning on the machine, all that appears is a black screen with the Apple in the centre and a white line indicating the time needed to open, which, when left running, will stick at under a minute to complete!
can anyone help please?
Thank you! Left it on overnight and it’s working fine this morning!!!
Must have taken a good 4 hours to go through - I am so relieved.
Great news my friend, take care! :)
Stuck mojave to monterey on imac
