Big sur upgrade help

Hey there!

I know you probably don’t want to hear this, but with this issue, you may have erase your Mac, and need to select:

Recovery Assistant > Erase Mac, then to “Activate” your Mac and Reinstall the OS.

After which, you can migrate your data from a Time Machine backup.

Likewise, if it’s locked to your Apple ID, you can erase it using the Find My iPhone application, or even iCloud.com.

Otherwise, can you say the make and model of your Mac? As with M1 Macs, this maybe relevant:

https://support.apple.com/en-us/HT211983

However, whether M1 or Silicon, old/new, that the previous steps should work regardless, if not, then that maybe the article to follow.

Its possible you are experiencing a different issue as well, do you know how much feee storage your HD had(s)? It no startup command works, then the previous steps may have to be followed. I believe using Recovery Assistant is the easiest way, although I hope you won’t need to do all that!

Hey again!

Well, if you were to, now, attempt the old version, you’d have to erase you Mac first, then either use a bootable installer, to install an Westport version of the OS, or start to recovery mode using Shift Command Option R......and update afterwards.

Its possible to use a Terminal to delete files while in recovery mode, I can help with that, however, I believe the ultimate fix will be reformatting the disk and reinstalling the OS, but can try to help otherwise.

I’ve found Big Sur needs a considerably Large amount of temporary storage, especially if booting from an older OS, but hope your HD isn’t overloaded.

Were you able to do a backup before upgrading the OS?

Can you get to recovery mode? Starting up your Mac holding Command R? If all you’re getting is the Recovery assistant, I’d probably use Recovery Assistant to erase it, or remove the Mac from your Apple ID using Find My, then remove your device from Find My, to then start a clean install.

Likewise, if you are able to get into recovery mode, can you show the available storage in Disk Utility > Macintosh HD - Data?

If starting up using Command R or Command Option R doesn’t work, in my experience with this issue, starting with Shift Command Option R will take you there, in which case, you’d be able to erase the disk, and reinstall the original OS your Mac came with, and upgrade to any OS available afterwards.

However if that’s the case, it would be better to just erase using Recovery Assistant then Reinstall the current OS if available to possibly avoid all this, you could try starting to date mode:

Startup your Mac and while holding Shift. But if that doesn’t work, I suspect you’d have to go the other route, but anything is worth a try! Let me know.

Hey again!

So you do have a Time Machine backup/external hard drive? If so then yeah, that shouldn’t be a problem. If not, let me know, but if you truly cannot get into Mac OS Utilities to make any changes, erasing may be the only option, hope that’s not the case though.....You did try starting up with Shift Option Command and R? If you can at least get there, and have an external drive to use, you may be able to save the data, or for that matter, possibly even run a disk repair or reinstall if the OS.

You mentioned having a bootable installer with an older OS......this may help though.

It you start your Mac holding the Option key, and the bootable installer connected, does it still take you to Recovery Assistant? If so, it probably means your HD is locked by either your Apple ID and/or File Vault, and the newer Startup Security Utility.

Likewise, if you are able to boot to that recovery mode or from a bootable installer, let me know, will help if I’m able to.

Hi,

you can change date & time from recovery mode using terminal.

Please refer below mentioned article, Hope it will help you.

https://www.filiotech.com/blog/support/change-date-recovery-mode/#one