How can I determine if File Vault decryption is really in progress?

Just booted into recovery mode again. Tried to reinstall OS. When I chose the disk and unlocked it, OS installation told me that I may not install to this volume as it is currently being decrypted.

Reluctantly, but it seems there was no other alternative..... I’ve just wiped and reinstalled. Apple support did tell me that this was going to be the only solution, but I hoped there was some other way. Seems a bit poor (to say the least) that by simply turning off FileVault you can end up in a situation like this :(

Booted into recovery mode, mounted disk, ran first aid. No issues found. Restarted and in exactly same situation - diskutil and fdesetup not reporting encryption/decryption in progress but EtreCheck and System Prefs (effectively) saying it is.

For me that would be “diskutil apfs list” which I’ve previously run (including in extended/verbose mode) and it doesn’t give any useful additional info. I really think I’ve exhausted all diskutil/fdesetup possibilities. Thanks for the suggestions though, John. Any other ideas which could help me determine if decryption is actually in progress (anyone) ?

Here you go, full output from diskutil apfs list. disk2s1 is what we’re talking about...

APFS Container (1 found)

|

+-- Container disk2 6A7041CC-1AA4-454F-92A8-30644AFA2741

   ====================================================

   APFS Container Reference:    disk2 (Fusion)

   Size (Capacity Ceiling):    3121506295808 B (3.1 TB)

   Capacity In Use By Volumes:   616107278336 B (616.1 GB) (19.7% used)

   Capacity Not Allocated:     2505399017472 B (2.5 TB) (80.3% free)

   |

   +-< Physical Store disk0s2 4E473AA2-112D-4BA6-95A3-52E21F0FBE1F

   |   -----------------------------------------------------------

   |   APFS Physical Store Disk:   disk0s2 (Main)

   |   Size:             121123069952 B (121.1 GB)

   |

   +-< Physical Store disk1s2 7F486618-9ED1-4DF4-9258-C2354E966304

   |   -----------------------------------------------------------

   |   APFS Physical Store Disk:   disk1s2 (Secondary, Designated Aux Use)

   |   Size:             3000383225856 B (3.0 TB)

   |

   +-> Volume disk2s1 F3A7DAC2-020F-3200-ACDE-B6F58140DD17

   |   ---------------------------------------------------

   |   APFS Volume Disk (Role):   disk2s1 (No specific role)

   |   Name:            Macintosh HD (Case-insensitive)

   |   Mount Point:         /

   |   Capacity Consumed:      604372119552 B (604.4 GB)

   |   FileVault:          Yes (Unlocked)

   |

   +-> Volume disk2s2 151DB652-5613-449F-8E0C-CE634A0B154E

   |   ---------------------------------------------------

   |   APFS Volume Disk (Role):   disk2s2 (Preboot)

   |   Name:            Preboot (Case-insensitive)

   |   Mount Point:         Not Mounted

   |   Capacity Consumed:      53202944 B (53.2 MB)

   |   FileVault:          No

   |

   +-> Volume disk2s3 6F0DA7E8-59AB-469D-ABA8-409211032A5E

   |   ---------------------------------------------------

   |   APFS Volume Disk (Role):   disk2s3 (Recovery)

   |   Name:            Recovery (Case-insensitive)

   |   Mount Point:         Not Mounted

   |   Capacity Consumed:      516952064 B (517.0 MB)

   |   FileVault:          No

   |

   +-> Volume disk2s4 0028F604-8F1F-45F3-ADAA-E75D3AEA2B1D

     ---------------------------------------------------

     APFS Volume Disk (Role):   disk2s4 (VM)

     Name:            VM (Case-insensitive)

     Mount Point:         /private/var/vm

     Capacity Consumed:      2147508224 B (2.1 GB)

     FileVault:          No

I did start the decryption when I said I did. After I started it, it did show some progress and was continually re-estimating the time to completion. That’s as I left it when I went to bed, to be presented with no progress bar next morning, but also no indication of completion.

If I click the lock icon and authenticate, the turn off option remains greyed out. As I said, Time Machine reports that encryption or decryption is in progress as does EtreCheck.

so back to my original question...

How can I determine if File Vault decryption is really in progress?

Yes, I’ve done that already. Tried connecting a new backup device and attempting to backup to it I got the msg that encryption or decryption was in progress so a backup would not take place until this had finished.

After conducting a quick risk assessment I’ve decided not to encrypt the iMac’s HD ;)

Thanks for your interest in my problem, John, and for the suggestions you made.