Recently I installed the Developer beta of macOS High Sierra (10.13). However, this makes my mac run INCREDIBLY slow, and I would like to revert back. Any hints on how to do this? Unfortunately I dont have a backup.
I tried downloading macOS sierra from the App Store, but it says the application is too old.
Once you update you cant go back down that is how it has always been with Apple. That is why they say upgrade to the beta's at your own risk.
Going into an Apple Store they might be able to downgrade it for you back to 10.12 by hooking it up to their internal servers but no promises that they can or would even be willing to do it since again 10.13 is in Beta and it is not even i Public Beta yet only Developer Beta.
restart computer pres alt + cmd + r this will start internet recovery lunch disk utilities format main drive " when it asks for name untiteld will show change to Macintosh HD" exit disk utillites the select install macOS when it asks for target select "Macintosh HD" (Might take a few atamts to get it to lanch internet recovery"
I just strugged with this on a 2013 MacBook Air. I was unable to use Disk Utility to reformat the SSD after upgrading to APFS:
So, moral of the story: if you need to revert from 10.13 beta back to an earlier OS, the only way to do it is to boot into Recovery mode and use Disk Utiilty there. Any other way will fail.
Update: In fact, I had to do this in two steps:
Then I was able to do a fresh install of 10.12 back on the Mac. (Note that this erases the entire drive, so is not a solution for the original question asked).
I was also experiencing issues reverting to 10.12 from 10.13. What worked for me was booting with the Option + Command + R keys held down, opening Disk Utility and erasing the APFS drive. I renamed to the new partition the standard "Macintosh HD", and, for my purposes, chose the journaled, encrypted option. I then closed Disk Utility and tried to reinstall the OS; however, it ran into errors after downloading and validating the installer. I had to shutdown the computer, restart it with the Option + Command + R keys held down, open disk utility and erase the drive again (oddly enough the partition that I previously created was not listed anymore). Once I created a new "Macintosh HD" partition, I closed Disk Utility and was able to go through the OS installation. My steps were similar to XMI's; however, I did not have to boot from 10.12 and run the Disk Utility from there. I hope this helps.
