I have done a terrible mistake and upgraded my macbook pro to macOS High Sierra Developer Beta.

I experience multiple malfunction behaviours, including:

  • Missing files right after upgrade.
  • Machine does not go to sleep when closing the lid (this might be the cause for other issues, since the macbook got VERY hot in my bag and shut down forcibly - twice...).
  • Mouse and keyboard does not function after login screen (not even USB mouse and keyboard. I had to connect via VNC to control the machine).
  • Finder won't launch (The application “Finder.app” can’t be opened.).

I would like to downgrade back to macOS Sierra (assuming the problems I described are reversible), but to avoid losing all data. Is it possible?


Same as my answer to No user to login in MacOS High Sierra, even though it may not be a strict duplicate...

I'd suggest nuke & pave, back to Sierra & HFS+, test the disk [as there are many utils that can test HFS but only one that can test APFS] then rebuild from backup.

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  • Can you explain / give reference to this "nuke & pave" process? – Elist Jun 12 '17 at 8:28
  • Start from a bootable USB, reformat the disk back to HFS+, install Sierra, migrate from your backup. – Tetsujin Jun 12 '17 at 8:30
  • OK, I'm backing up my data. Any reason I won't be able to reinstall from internet instead of a bootable disk? – Elist Jun 12 '17 at 12:47
  • If the disk has been reformatted to APFS at the upgrade, I'm not sure whether you can go back to HFS from internet recovery. Might be worth checking. btw, Time Machine won't let you go 'downhill'. You'll need a backup from before you upgraded. See apple.stackexchange.com/questions/271104/revert-to-el-capitan for a cautionary tale. – Tetsujin Jun 12 '17 at 13:03
  • Thanks, I think I'll give internet recovery a try after full backup. Will update when I have any findings. – Elist Jun 12 '17 at 13:10

You should make a back up of the Mac immediately and then decide if you want to try running an old OS on the new user data or if the fastest path to stability is to wipe the machine and hand recover files from the backup.

Ideally - you have a back up of the machine from before you let the upgrade run and touch all the settings, preferences, data storage formats and potentially the file system itself.

This lets you keep hope that the next beta gives you enough stability to work and avoid the work needed to back port new files to an old os.

Nothing here is no - all Apple upgrades are one way and if the migration fails you need a backup to go back. The one thing that’s substantially new here would be a new file system and a new .0 beta which is generally the least stable OS release you will ever install.

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