I have a 1 TB external drive I use for Time Machine, and as manual backup external drive. It is encrypted.

I started to convert it back to normal. I was able to mount it correctly several times while the conversion was in progress, but now it is not working anymore. Can't be mounted.

diskutil corestorage list

CoreStorage logical volume groups (1 found)
+-- Logical Volume Group 390B29FA-501C-4A34-BCE9-A2249F1FA2A3
    Name:         HDEXT1TB
    Status:       Online
    Size:         999860912128 B (999.9 GB)
    Free Space:   5943296 B (5.9 MB)
    +-< Physical Volume FB6151D3-4BEA-4C69-A744-A17B9AE18262
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk2s2
    |   Status:   Online
    |   Size:     999860912128 B (999.9 GB)
    +-> Logical Volume Family 21CF48F7-8D6D-4990-A2E6-C21680852F03
        Encryption Type:         AES-XTS
        Encryption Status:       Unlocked
        Conversion Status:       Converting (backward)
        Reversion State:         Decrypting
        High Level Queries:      Not Fully Secure
        |                        Has Visible Users
        |                        Has Volume Key
        +-> Logical Volume 45E49F43-C577-415F-B606-3295EB25FAB3
            Disk:                  disk3
            Status:                Online
            Size (Total):          999502643200 B (999.5 GB)
            Conversion Progress:   57%
            Revertible:            No
            LV Name:               HDEXT1TB
            Volume Name:           HDEXT1TB
            Content Hint:          Apple_HFSX

diskutil mount readOnly 45E49F43-C577-415F-B606-3295EB25FAB3
disk3 is a CoreStorage Logical Volume which failed to mount

diskutil corestorage decryptvolume 45E49F43-C577-415F-B606-3295EB25FAB3
Started CoreStorage operation on disk3 HDEXT1TB
Error: -69649: This Core Storage logical volume is already decrypting

Is there any way to mount it again? It seems to be still decrypting, do you think I can simply leave it attached to the Mac even if not mounted?

  • 1
    Assuming conversion rate is 20 MB/s and making and drinking a coffee takes 5 minutes, drink another 71.6 cups. Then check back! – klanomath Mar 26 '17 at 10:51


ps aux |grep disk3

this reported a fsck_hfs -y on disk 3, consuming either a lot of cpu as well as keeping the drive like as locked.

killed the related PID

then the disk mounted itself immediately. the conversion is still in progress, 60% now, but at least I can access files.


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