enter image description hereSo after updating to Big Sur a lot of problems hit my mac all at once and I decided to roll it back. Since I didn't make a backup (dumb move I know) I had to basically start from scratch. Before I did so I backed up my current state to an external ssd and then erased the mac via recovery mode. Now its in recovery mode and the reinstall macOS keeps giving me an error and I can't restore from the Time Machine backup as it starts looking for the SSD but never finds it. I would like to try and get it running mojave or catalina or at least anything because in its current state it's useless

Macbook pro 2016 500GB SSD

  • 1
    You said "you didn't make a backup" but then you "backed up the current state." Was that the current state of Big Sur? Then, are you trying to restore a Big Sur backup to an earlier version? That won't work.
    – Allan
    Nov 15, 2020 at 18:28
  • oh alright i wasn't aware of that. But im trying to do "restore from time machine backup"in the macOS recovery mode. It has no OS installed at the moment. Will it not work in those conditions? Nov 15, 2020 at 18:36
  • If your Time Machine was made with Big Sur, trying to boot form that will boot and attempt to install Big Sur. See bmike's answer below to boot Internet recovery. Erase the whole drive as advised, install a clean OS, then use Migration Assistant to copy over whatever data you had backed up to TM while using BS.
    – Allan
    Nov 15, 2020 at 18:41
  • I'll try and delete everything I can. But right now I have two internal disks and one disk image. Is that normal? Also when I try to erase anything it says "erase process has failed. Click done to continue. Wish I could take a picture but maybe I'm just oblivious but I don't see that option here. Nov 15, 2020 at 18:47
  • That sounds like you have a fusion disk (usually an SSD and a mechanical HDD logically combined to make one drive). See this answer for some tips to erase as you don't have to "break it" to wipe it clean. There's also info on the fusion drive. It might help if you edit your question with the exact model of your Mac, the drive config (CPU and memory aren't relevant) and what you want the end result to be (i.e. I want it to be running El Cap again). This helps us by knowing what you have and where you want to go.
    – Allan
    Nov 15, 2020 at 18:51

1 Answer 1


Yes. Be sure you erased the entire drive from recovery. Some people erase only a volume and get stuck, the entire drive should be erased for your downgrade to work the fastest.

Which of these keys are you using?

For your case, you want Shift-Option-⌘-R

Reinstall the macOS that came with your Mac, or the closest version still available.

  • First of all thank you for replying so quick. I selected "erase mac"or something along those lines from the apple logo in recovery mode. Do i need to go into disk util and erase every single entity there? Nov 15, 2020 at 18:31
  • Without seeing the exact screen shot I can’t tell if you selected the correct spot. I would do the erase again with the Apple article pulled up so you know you picked the correct item to erase. There are 3 to 5 items, so odds are you picked the wrong item if you didn’t know you selected the correct target. @GuilhermeBarata so no, you don’t have to erase them all, just the one correct item. The rest fall like dominoes
    – bmike
    Nov 15, 2020 at 20:01
  • @GuilhermeBarata in your screen shot you chose a wrong selection.
    – bmike
    Nov 15, 2020 at 20:02
  • Yeah i deleted it and i got the install going but now it's presenting me with a... forbidden sign? a circle with a slash across. I cant catch a break. Any ideas? Nov 15, 2020 at 20:17
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    i got it fixed its completing the instal right now. Thank you very much for your help and time. You were great help too Nov 15, 2020 at 21:32

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