Resolved Time Machine Volume not showing up after "disk was not ejected properly"

[maxmaut]

So I'm using an external USB 3.0 enclosure Age Star with 3GB Hitachi disk inside it as my Time Machine storage and as a general storage for music/video files.

It was working just fine till this morning. Now, when I connect it, it does not show up in MacOS. The enclosure has two indicators, for when the disk is powered and when it's in use. When I hook it up to any of the macs I own, the "in use" indicator starts blinking (it does not blink when I hook it up to a windows laptop). Also the sound that the disk is making corresponds to the sound it was making when it was in use.

When I try to launch Disk Utility, it get's stuck on "loading disks" spinner forever. If I disconnect the drive, then launch Disk Utility and connect it back, it does not show up there.

I did the PRAM reset with the disk connected, it did not help.

I hooked it up to a windows laptop, it did not show up either.

I think there's a very high probability it was not disconnected "properly", probably simply powered off (maybe while in use). What issues could this cause?

If it's the drive that is causing issues, what are the chances to restore the information that's on it?

 

[chscag]

I would first remove the Hitachi from the enclosure and instead use an adapter or place it in another enclosure if one is available. There's a chance the enclosure is defective rather than the drive itself. If that's the case, your data should be OK.

 

[maxmaut]

So the issue was way different, and it seems I've fixed it.

I'll leave it here for future generations.

The issue occurs while the disk is in use and it get's unmounted by plugging it off, or by powering it off (You get the message "disk was not ejected properly").

I had a time machine backup going on and a virtual machine running from the same drive.

After disconnecting it, and connecting again - it was not showing up in MacOS or Windows.

The way to diagnose if your issue is the same - go to System Information utility, and see if your drive is showing up under USB section. Mine was there, so it was clear that it's not the issue with the drive itself.

The thing is - when it is trying to get mounted, OSX is launching a process "fsck_hfs". It's the same process that appears when you're performing "first aid" on the disk, so the OSX is trying to check the disk before mounting it.

What I did - I force quit this process in Activity Monitor utility, then the disk appeared in Disk Utility, and I was able to perform First Aid on it manually.

After that Time Machine was refusing to use the disk and complained it was "read only", so I had to turn Time machine off, unmount the disk, restart, mount the disk and enable Time Machine again.

Right now it is in "preparing backup" state, so it seems fine.

Somewhat useful links:
http://apple.stackexchange.com/ques...ed-in-disk-utilities-but-found-in-system-prof
http://apple.stackexchange.com/questions/221730/how-to-mount-a-disk-that-was-not-ejected-properly
https://www.lifewire.com/fix-time-machine-errors-2259975