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

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??

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!!

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

Apple - this is appalling. I moved to Apple because Windows updates were a disaster. My MacBook has been dead for 5 days now. Apple support told me to create space by moving stuff to my other Mac. Fine - spent £40 on a Thunderbolt cable. Cleared a load of space. Still have the same issue.

Surely it is coding basics to ACCURATELY CHECK there is enough disk space before updating an OS. My seven year old could tell you that.

Next step shift the rest of my stuff. Wipe the hard drive and have another go.

Apple has become a bunch of hopeless amateurs.

Oh no! This is exactly what’s happening to me atm — I took my mb air to an authorised tech shop yesterday and have been waiting to hear back. Things are slower here in Portugal. I’m praying they don’t have to wipe it.

Update: I’m having to erase my laptop and start from scratch. Luckily there is nothing of importance that will be lost. Tech said since there are enough people experiencing the same problem that the engineers are looking into it more deeper. Still doesn’t help my problem right now

I cannot believe this problem had been going on since November and Apple hasn’t fixed it. I just did the upgrade to Big Spur and am now stuck in this loop. WTH! So incredibly frustrating. If I didn’t have enough space on my HD why on earth did it allow me to even begin the update.

I got a snarky “support” person via chat today who basically shamed me for not ensuring I double backed up everything before I did this update. um, hey Apple, maybe don’t make a computer update that has the major potential to put people’s computers out of commission and potentially wipe them clean?! they are seriously 0 help with this. infuriating.

I did the step to format my external HD in Disc Utility, but I don't know how to do the next step... is there a way to drag and drop the update into the hard drive, or how do you do that from Disc Utility?

So this command is assuming the volume with your data is called “Macintosh HD - Data“, the name of your home folder is “username“, and that the name of your backup drive is “backup” (And that the volume is already mounted/unlocked).

cp-r -v /Volumes/“Macintosh HD - Data”/Users/username/ /Volumes/backup

You can adjust the names accordingly, I usually just target the user folder which stores the majority of your data, but the command could be adjusted to target other folders/directories, such as Pictures or Music, etc.

Likewise I make sure the external hard drive is formatted as HFS+ (Mac OS Extended Journaled) and GUID partition map.

There are other ways to save the data, such as a disk image, or installing the OS on an external disk, booting from that and grabbing what you need, but I find this way is quicker and works just as well, if not better. Especially if your choices of saving your data are slim, this is an effective step to take before erasing, although nothing is a sure deal, setting up Time Machine to prevent data loss is the way to go, but I know sometimes this isn’t done, or can’t be for whatever reason.