Big Sur installation stuck at "Less than a minute remaining..."

I got it to work finally. Just took a lot of tries. Finally booted the internet recovery partition, installed Yosemite, logged in, downloaded Big Sur, installed that, logged in, restored from backup. Took three days and lots of reboots.

I tried to upload big sur on a 2013 mac book pro. Stuck at less than 1 minute remaining screen. Tried safe mode start up with no success. Have rebooted a dozen or so times. No success. Had Sierra OS and no indication this would fail. HELP please. Have time machine backup.

Just when I thought it was stuck forever on less than a minute remaining and started searching for solutions online, it to reboot. So may be a little patience works sometime. It was stuck for ten minutes or so.

Hi! Thanks for sharing the information! However I got one question, how did You access the internal drive (whole system in on external) and erased files? I can’t access the HD even while disc utility shows its full

A friend of mine who is far more educated than I walked me through accessing the internal HD files through the terminal view. I wish I could reiterate the commands he had me type in but I can't. It's super frustrating how apple hides certainly files that you can't access otherwise.

Do Apple have more input to this?

I have the exact same problem - running a 2015 MacBook Pro with 250Gb HD, and High Sierra, I decided to update to Big Sur. Followed Apple instruction to do so through the App Store. After clearing enough space the install was allowed, ran, and got stuck at 1 min for 12 hours.

Tried to reboot and run safe mode. Holding shift while booting, I get the Apple Logo, about 30% progress quickly, then black screen, then it repeats.

Tried to reboot and run Recover Mode. Tried to reinstall Big Sur, and told neither partition has enough space. Tried TimeMachine and after 10 mins it crashes saying “error occurred”.

Seems the only option to try next is TimeMachine onto my data partition and lose anything I might not have backed up. Though that probably won’t work either.

Would really appreciate help. Big Sur allowed and install with 21Gb available and now crashing saying not enough space?

I can’t get back to my desktop, just keeps going back to the “about 8 minutes remaining” screen. I’ve tried holding space bar down then entering in my computers password (says my password is not correct), tried CMD R and CMD RP, goes right back to the updating screen. I’ve moved buildings with different Wi-Fis (both strong connections)!! I’m lost at this point. Does this software update delete all your documents??

So I managed to fix eventually, partly with luck though (and the post from Maddie above).

hold power to switch off, then hold cmd+r and power on again. you then get the recovery screen and I tried to reinstall Big Sur, but neither my HD nor Hd-Data had room, claiming approx 15GB and 400MB required.

I then rebooted and hold alt/option to boot into some secret magic mode that allows you to select your normal HD as the OS disc, and came back to my old High Sierra desktop. I then cleared lots of files onto an external drive and repeated from the cmd+r step above.

now the mad said I needed 4GB and 700MB respectively!! I repeated, and at my desktop I noticed the Hd disks NEVER reported more than 16GB total available, despite my moving files. I tried this cycle a few times and each time, the Big Sur install gave back random amounts of disk space required - this went up and down on each cycle and made absolutely zero logical sense - Apple, this is serious cause for me to move away from your products!!! Total rubbish.

I eventually decided to run the Big Sur update from my desktop again, since the recovery option would never allow it due to disc space, and it then ran fine as long as I selected HD-Data. It then updated fine, opened up Big Sur, and now reporting about 105GB free space!! Wtf right.

probelm now is I have an old HD (presumably with a High Sierra copy somewhere on it), an HD-Data (Running Big Sur) and an HD-Data-Data (for my Data) - total mess, so trying to figure out how to do a clean install (and migrate all my Lightroom & photoshop data!).

It works. But I am not happy with Apple at all. Total joke.

To me the ‘Option’ start doesn’t work - computer connected to WIFI somehow tries to load a system but doesn’t complete.

the fact I’ll loose files of my job and the fact I’m stuck for 2 days with this nonsense make me really think of moving away from Apple - this is ridiculous mistake and way to serious for the price of the product.

Hi CraigT, have you had any progress? I'm in a cycle of your first two steps. I'm not technical at all so not sure what the reboot and recover mode is. i'm scared to mess around as i dont know what i would be doing. Driving me insane. Should never have accepted the update before work!!

Not sure what to suggest if the Option / ALT key doesn't work, as that was critical for me to get this going. Alternatively, you could investigate installation onto an external drive, then once into your OS; clean up space, rinse and repeat back onto your Mac HD?

Reboot and recovery mode is holding power button until power off, then hold CMD+r while power on. You will go into a recover mode screen where you can try to reinstall the OS on a specific drive, or roll back to a backup with TimeMachine (this crashed for me though).

I ended up holding ALT / OPTION while booting up, that took me to some boot mode allowing me to enter my old OS. From there i cleaned a lot of space, then ran the Big Sur installed again which worked (sort of).

Thank you! I will try this now and see what happens. I got a screen at one of my restart cycles earlier that asked for another computer and a thunderbolt cable, to connect to and use as a drive?? neither of which i have. Nor would I have a clue what to be doing with. Thanks for your help. I'll try the reboot and recovery now and hope for the best.

I’ve tried every alternative mentioned here to no avail. Recovery mode doesn’t recognise my password so I’m stuck. Back in the countdown installation loop for lack of ideas at this point. This is beyond frustrating – I’ve wasted a whole afternoon of work.

Yep! Everything! 🙈 im one of those stupid people that saves everything to the desktop.

if not too late, persist with support that you dont want to erase your mac and you need a resolution. I was worn out by the end of it and succumbed