Encrypted backup HD not working, welp?

[KoolAid-Drink]

I have three external hard drives; all of them Time Machine backups and encrypted. When plugging in and mounting two of these three hard drives, the unlock dialog comes up and I'm able to unlock them, no problem. However, the third one isn't working properly. The unlock dialog comes up, I type in the password, and then the entire dialog just greys out then eventually disappears, and the HD never mounts to the desktop. I know it's not the password, because if it was the password, it'd shake the dialog.

When opening Disk Utility while this HD is plugged in, DU never loads but instead, has a spinning gear and a message saying: "Loading disks."

I restarted and tried to boot from that HD. Surprisingly, it works, but DU does the same thing when opening it from "OS X Utilities."

Very odd situation and I'm not sure what to do. Any thoughts? Thanks!

 

[JohnDS]

If you can boot from the disk, try unencrypting it.

 

[KoolAid-Drink]

If you can boot from the disk, try unencrypting it.

How? Disk Utility won't work, even in Recovery Mode - the spinning gear keeps spinning endlessly.

 

[dmnc]

Check the SMART status. Maybe the disk is broken...

 

[JohnDS]

If you can boot from the disk and it was encrypted using File Vault, go to System Preferences > Security and Privacy > File Vault.

Click on the lock at the bottom left to unlock it, the click on the button to turn off File Vault.

 

[KoolAid-Drink]

If you can boot from the disk and it was encrypted using File Vault, go to System Preferences > Security and Privacy > File Vault.

Click on the lock at the bottom left to unlock it, the click on the button to turn off File Vault.

I'm not sure how - when I did this, it showed my startup HD (which isn't encrypted) as off. There was no option to turn off encryption on the external HD. When I boot from the external HD partition, it boots into the OS X Utilities partition, which does not have a System Preferences. Am I missing something?
[doublepost=1468376630][/doublepost]

Check the SMART status. Maybe the disk is broken...

Don't think you can check the SMART status of an external HD?

 

[KoolAid-Drink]

Update: I ended up forcing unlocking the HD in Terminal, which still didn't make it show up on the desktop. However, I was able to dencrypt it and now the HD shows up as normal. Very odd. When I have time, I'll do a deep fsck on the HD and then re-encrypt it. Hopefully this wasn't some kind of corruption with FV2, but rather, an oddity with the HD itself.

 

[dmnc]

Update: I ended up forcing unlocking the HD in Terminal, which still didn't make it show up on the desktop. However, I was able to dencrypt it and now the HD shows up as normal. Very odd. When I have time, I'll do a deep fsck on the HD and then re-encrypt it. Hopefully this wasn't some kind of corruption with FV2, but rather, an oddity with the HD itself.

That's very strange...but good that it's back and running!
In response to your other comment: yes, you can check SMART status of an external drive but to do so you have to install an external 3rd party kernel extension called SAT SMART Driver, which is free and open source. The developer of DriveDX recommend it and I haven't had any problems with it.