If macOS High Sierra shows your password instead of the password hint for an encrypted APFS volume
Take steps to protect your data if you see your password instead of your password hint for an encrypted APFS volume.
Your password might be displayed instead of your password hint if you used the Add APFS Volume command in Disk Utility to create an encrypted APFS volume, and you supplied a password hint.
Changing the password on an affected volume clears the hint but doesn’t affect the underlying encryption keys that protect the data.
Apple recommends that you take these steps to guard the security of your data.
Encrypted APFS volumes that you created using any other method are not affected.
Protect the encrypted APFS volume
Follow these steps to update macOS High Sierra, and then back up, erase, and restore the encrypted APFS volume.
Install the macOS High Sierra 10.13 Supplemental Update from the App Store updates page.
Create an encrypted backup of the data in your affected encrypted APFS volume.
Open Disk Utility and select the affected encrypted APFS volume in the sidebar.
Click Unmount to unmount the volume.
Click Erase.
When asked, type a name for the volume in the Name field.
Change Format to APFS.
Then change Format again to APFS (Encrypted).
Enter a new password in the dialog. Enter it again to verify the password, and if you’d like to, provide a hint for the encrypted APFS volume. Click Choose.
Click Erase. You can see the progress of the Erase process.
Click Done when the process is complete.
Restore the data that you backed up in Step 2 to the new encrypted APFS volume that you just created.
Protect other accounts
If your disk password for any affected encrypted APFS volume is the same as the password that you use for a macOS user account or an internet service, you should change the password of the user account or internet service.