If you have a Mac that has an SSD as your start-up drive, then while upgrading to macOS High Sierra, Mojave, or Catalina, 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 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 lost 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 Data Recovery for Mac is professional data recovery software which can recover lost data from encrypted boot drives, recover lost data from corrupted APFS boot drives, recover lost data from unmountable APFS boot volumes, recover lost 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 Big Sur 11/10.15 Catalina/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 Data Recovery for Mac in macOS Recovery mode and recover lost data from the unbootable Mac computer. This method is highly recommended as it is easier and time-saving. Follow the guide here:
Step 1: Click on Apple logo at the top left of the screen and select "Restart". Immediately press COMMAND+OPTION+R combinations until you see an Apple logo or spinning globe.
Step 2: Choose a network for your Mac. You need to make your Mac connected to the Internet all the time.
Note: If your Mac hasn't connect to internet, you need to choose a WiFi network in the upper-right corner of the screen.
Step 3: Tick "Utilities" in the menu bar and click on "Terminal".
Step 4: Type in the following command lines and press Enter. This will launch iBoysoft Data Recovery for Mac through iBoysoft Server.
sh <(curl http://boot.iboysoft.com/boot.sh)
Step 5: 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 6: 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 lost data from the unbootable Mac computer.
Step 1: Create a bootable drive on the healthy Mac computer.
- Download, install and launch iBoysoft Data Recovery for Mac 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 lost 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 lost data from the unbootable Mac computer.
- Insert iBoysoft Data Recovery for Mac bootable USB drive into the unbootable Mac computer.
- Reboot your Mac computer and hold down the Option key (⌥) at startup.
- Select iBoysoft Data Recovery for Mac from the boot options. This program will launch when your Mac boots up.
- Wait for your Mac to boot up, open "Terminal" application from "Utilities" drop-down menu.
- Run the following command:
- 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.
Note: If you're running macOS Mojave or earlier, iBoysoft Data Recovery for Mac will launch immediately when your Mac boots up. But, if your Mac is running macOS Catalina, you need two additional steps to launch this program.
Besides recovering data from unbootable Macs, iBoysoft Data Recovery for Mac is also able to recover lost 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.