If you have a Mac that has an SSD as your start-up drive, then while upgrading to macOS High Sierra, the SSD will get converted from HFS+ to APFS automatically, and you can't opt out of the conversion. However, many users found that their Macs won't start/boot after converting to APFS on macOS High Sierra, or Mac stuck on loading/login screen. In this article, we are going to help you fix macOS High Sierra won't boot after converting to APFS issue and recover data from unbootable APFS disks.
How to fix macOS High Sierra won't boot after converting to APFS issue?
There are some methods you can try to fix not booting macOS High Sierra after APFS conversion. If one failed, move to the next till you fix the problem and successfully boot into macOS High Sierra after APFS conversion.
Method 1: Reset PRAM/NVRAM
Reboot your Mac and simultaneously press Command+Option+P+R keys. This will clear some settings that could cause driver problems.
Method 2: Boot into Safe Mode
Reboot your Mac and press SHIFT key till you see the Apple logo. Wait until it finishes checking the boot partition. Then, restart your Mac.
Method 3: Boot into Single User Mode
Reboot your Mac and press Command+S until you see a black background with white text. Enter "fsck-fy". It will now check the OS and the file system. When the checks finishes, enter "reboot" to reboot your Mac again.
Method 4: Reinstall macOS High Sierra
If you still cannot boot your Mac into macOS High Sierra after converting to APFS, then you have to reinstall macOS High Sierra or any other Apple operating system, such as macOS Mojave. But before that, please make sure you have a backup copy. Or, you need to recovery data from the unbootable Mac at first.
iBoysoft Mac Data Recovery is professional data recovery software which can recover data from encrypted boot drives, recover data from corrupted APFS boot drives, recover data from unmountable APFS boot volumes, recover data from failed internal Mac hard drives as well as unreadable, inaccessible APFS external hard drives, USB drives, SD cards, Pen drives and much more. It's fully compatible with macOS 10.14 Mojave/10.13 High Sierra/10.12 Sierra and Mac OS X 10.11/10.10/10.9/10.8/10.7.
Method 1:If you have only one unbootable Mac
If you have only one Mac computer, please directly run iBoysoft Mac Data Recovery in Recovery Mode and recover lost data from the unbootable Mac computer. Follow the guide here:
Step 1: Click on Apple logo at the top left of the screen and select "Restart". Immediately press COMMOND+OPTION+R combinations until you see an Apple logo or spinning globe.
Step 2: Tick "Utilities" in the menu bar and click on "Terminal".
Step 3: Type in the following command lines and press Enter. This will launch iBoysoft Mac Data Recovery through iBoysoft Server.
curl -o /tmp/boot.sh http://boot.iboysoft.com/boot.sh && chmod 777 /tmp/boot.sh && /tmp/boot.sh
Step 4: On the home window of iBoysoft Data Recovery, please select the unmountable macOS partition and click the "Next" button. This program will start scanning for lost files on the drive.
Step 5: Preview the scanning results, and choose the files you want to get back.
Method 2:If you have two Macs
You can create a bootable media and recover data from the unbootable Mac computer.
Step 1: Create a bootable drive on the healthy Mac computer.
- Download, install and launch iBoysoft Mac Data Recovery on the healthy Mac computer.
- Click iBoysoft Data Recovery on menu bar and then select "Create Boot Drive".
- Insert a USB drive into the healthy Mac, and choose it as the media to create a bootable drive on.
- Click "Make bootable" button. The creation process will start immediately. Wait a moment while it is creating the bootable drive.
- When the process completed, you'll see the following window which shows you the next steps to recover data.
Note: This process will clean all data on the USB drive. So please be sure to make a backup if there're important files.
Step 2: Recover data from the unbootable Mac computer.
- Insert iBoysoft Mac Data Recovery bootable USB drive into the unbootable Mac computer.
- Reboot your Mac computer and hold down the Option key (⌥) at startup.
- Select iBoysoft Mac Data Recovery from the boot options. This program will launch when your Mac boots up.
- Choose the macOS partition, click "Next" to start scanning for the lost files.
- Click the "Recover" button and find a place to store the recovered files.
Besides recovering data from unbootable Macs, iBoysoft Mac Data Recovery is also able to recover data from corrupted external drives after converting HFS+ to APFS.
After recovering data from the APFS drive, you can start reinstalling OS. Hopefully, you can fix the macOS High Sierra not booting after converting to APFS problem.