A few weeks ago I told all of my three external hard drives to encrypt. This went well, macOS (10.13.4) converted them to an APFS formatted encrypted volume, except for one drive. This drive doesn't complete it's encryption as it seems. Right-clicking on it shows a greyed-out entry for the "encrypt volume" command. How to fix?
When you update to macOS High Sierra, macOS Mojave or macOS Catalina, your Mac internal hard drive will automatically convert HFS to APFS (encrypted), and you can format or convert external drives to APFS (encrypted) based on your actual needs. But just like the above example, sometimes, encryption of APFS volume won't finish on High Sierra.
Why encryption of APFS volume won't finish on High Sierra?
The main reason why APFS volume won't finish on High Sierra is corrupted file system and damaged partition. In this situation, the operating system is unable to recognize the internal memory and fails to encrypt APFS volume on High Sierra.
How to fix 'encryption of APFS volume won't finish on High Sierra'?
As APFS volume encryption paused/stuck is caused by file system corruption, the most effective solution is to reformat the corrupted APFS encrypted volume. But the encrypted APFS volume must contain your important files. In this case, you have to restore lost files from the encrypted APFS volume to another volume firstly and then reformat the encrypted APFS volume.
Step 1: Recover lost data when encryption of APFS volume won't finish on High Sierra
iBoysoft Data Recovery for Mac is highly recommended to recover lost data when encryption of APFS volume won't finish on High Sierra. The powerful data recovery tool can recover lost data after APFS encryption froze/stuck/interrupted/paused, recover lost data from encrypted APFS startup drive/external drive, recover lost data from formatted, unmountable, unreadable, inaccessible APFS drive, recover deleted/lost APFS partition.
Besides, iBoysoft Data Recovery for Mac also supports data recovery from HFS, HFS+, exFAT, FAT32 drive on macOS 10.15/10.14/10.13/10.12/10.11/10.10/10.9/10.8/10.7.
Tutorial to recover lost data when encryption of APFS volume won't finish on High Sierra
1. Free download, install and launch iBoysoft Data Recovery for Mac.
2. Click "Find Lost APFS Partition" on the top right corner. Then you will see all connected hard drives.
3. Select the drive which contains your APFS encrypted volume and click "Next" button. The software will list all APFS volumes on the selected drive.
4. Choose the APFS encrypted volume that you want to recover lost data from and click "Next".
5. Enter the correct password and click "OK" to start searching for lost files on the volume.
6. Preview the listed searching results, choose files you need, then click "Recover" to get lost files back.
7. Go through to make sure you have all the lost files back.