"I converted the partition to APFS using the Disk Utility, and High Sierra would not boot. My Macbook Pro suddenly stopped running, showing me an unmountable error happened to my APFS boot volume. I have important files on this APFS volume, is there any to recover data from unmountable APFS boot volume? Thanks in advance!"
Have you ever troubled by the unmountable APFS boot volume error? Actually, this error not only happens to all Mac users in the middle of macOS High Sierra installation but also appears during computer startup, even when you don't make any change to Mac computer. The unmountable APFS boot volume error might be caused by virus attack, human error, corruption of head file, bad sector, catalog files node corruption, software or hardware problem, etc. No matter what leads to the unmountable APFS boot volume error, you have no chance to access the data on the APFS volume. The most important thing is to recover data from unmountable APFS boot volume.
Is it possible to recover data from unmountable APFS boot volume?
The answer is "Yes", but to recover data from APFS hard drive is complex and troublesome. Firstly, the unmountable APFS boot volume error comes with dead/crashed Mac computer. Secondly, APFS is a new and complex file system, so a few data recovery software can support it. Thirdly, when you upgrade to macOS High Sierra, your boot drive will not only be automatically convert to APFS, but also will be formatted to APFS (encrypted) if you locked the boot drive by FileVault before. There is no data recovery program except iBoysoft Mac Data Recovery which can recover data from encrypted APFS boot/startup drive.
Here is a short video about how to recover data from unmountable APFS boot volumes:
How to recover data from unmountable APFS boot volume?
As the best APFS data recovery software, iBoysoft Mac Data Recovery can easily recover data from unmountable APFS startup disk, recover data from encrypted APFS boot/startup drive, recover deleted/lost data from APFS partition, recover data from formatted APFS hard drive, recover data from inaccessible APFS drive, recover data from corrupted APFS drive, recover deleted/lost APFS partition, etc. in macOS Catalina 10.15/Mojave 10.14/High Sierra 10.13/10.12 Sierra and Mac OS X 10.11/10.10/10.9/10.8/10.7.
Aside from APFS data recovery, iBoysoft Mac Data Recovery also supports to recover data from drives formatted as other file system (HFS+, FAT32, exFAT, etc.). With this tool, we will no longer be annoyed by data loss, no matter losing data from hard drive, external hard drive, USB flash drive, memory card or pen drive.
Solution 1: If you have only one unbootable Mac computer
If you have only one Mac computer, please directly run iBoysoft Mac Data Recovery in recovery mode and recover lost data from the unmountable APFS boot volume.
Step 1: Click the Power button to turn on the Mac, and immediately press COMMAND+OPTION+R keys until you see the spinning globe. This will boot your Mac into Recovery Mode.
Step 2: Go to Utilities > Terminal from the menu bar to open Terminal.
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: Type in the following command and press Enter. This will launch iBoysoft Mac Data Recovery through iBoysoft Server.
s='/private/var/tmp/boot.sh' && curl -o $s http://boot.iboysoft.com/boot.sh && chmod 777 $s && $s
Step 4: Once you launch iBoysoft Mac Data Recovery, you need to choose the unmountable APFS boot volume 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.
Step 6: Click the "Recover" button. You need to specify a different location to store the recovered files.
Solution 2: If you have two Mac computers
You can create a boot drive to start up the unbootable Mac computer and then recover data from the unmountable APFS boot volume.
Step 1: Download iBoysoft Mac Data Recovery on another Mac computer.
Step 2: Install and launch iBoysoft Mac Data Recovery.
Step 3: Click iBoysoft Data Recovery on menu bar and then select "Create Boot Drive".
Step 4: Insert a USB drive into your Mac computer. Select it to create a boot drive.
Step 5: Click "Make bootable" button. The creation process will start immediately.
Warning: This process will erase all data on the USB drive. So please be sure to make a backup if there're important files.
Step 6: After that, please insert iBoysoft Mac Data Recovery bootable USB drive into the unbootable Mac computer, and then press the Power button and Option key (⌥) to start the computer up.
Step 7: Select iBoysoft Mac Data Recovery from the boot options.
Step 8: Follow the wizard to scan for lost data on the unmountable APFS boot volume.
Step 9: Preview and select the files you want to get back, and then click the Recover button.