iMac and external hard drive help please!

[Nele]

I had an iMac and had the time machine backing up onto a g-drive 6TB external hard drive.
My iMac died (well, the hard drive and then something else) so instead of getting it fixed I ordered a new one.
But in the mean time got a lend of an iMac from a friend.

Now, when I plug in the external hard drive (with my whole life on it)..it is not mounting.
The moment the external hard drive is plugged in, it starts doing something (spinning) ..nearly seems like it’s trying to do another back up or god knows what..
And I am unable to eject it.

It shows up in disk utility but is greyed out. I tried clicking “mount” but it doesn’t mount.

I also tried to eject it in terminal using “eject disk3” but it failed to eject.
And “unmount disk3” “unmount force disk3”..

So I don’t know what to do.

Is there a command to stop the external hard drive from Doug whatever it is doing?

I hope someone can help as there is an awful lot of things on that hard drive

I presume the external hard drive wasn’t ejected properly when my previous computer broke so it’s just trying to do something and is running the process over and over again

Thanks!

 

[Fishrrman]

What year was your ORIGINAL iMac made?
What OS was on it?

What does it do when you press the power-on button?

 

[Nele]

What year was your ORIGINAL iMac made?
What OS was on it?

What does it do when you press the power-on button?

The original iMac was 2016 and it had the latest OS on it (I can’t remember what it was called ? but it was updated)

The iMac I have at the moment is 2013 and has Catalina.

Sorry, the power on of the iMac? It has an apple logo, loads up and then goes into the login screen

 

[Fishrrman]

OP:
"Sorry, the power on of the iMac? It has an apple logo, loads up and then goes into the login screen"

Is this your original iMac?
If so, isn't that what it's supposed to do?
That is
- press power on
- apple appears
- OS loads with progress bar
- login screen appears

What happens when you log in?

 

[Nele]

Yes, the computer is fine

the issue is with my EXTERNAL hard drive, where I have the time machine back up from my previous computer.

When I connect the USB to this iMac it says the hard drive is not mounting (explained it longer in the original post)

 

[macfoofoo]

I had an iMac and had the time machine backing up onto a g-drive 6TB external hard drive.
My iMac died (well, the hard drive and then something else) so instead of getting it fixed I ordered a new one.
But in the mean time got a lend of an iMac from a friend.

Now, when I plug in the external hard drive (with my whole life on it)..it is not mounting.
The moment the external hard drive is plugged in, it starts doing something (spinning) ..nearly seems like it’s trying to do another back up or god knows what..
And I am unable to eject it.

It shows up in disk utility but is greyed out. I tried clicking “mount” but it doesn’t mount.

I also tried to eject it in terminal using “eject disk3” but it failed to eject.
And “unmount disk3” “unmount force disk3”..

So I don’t know what to do.

Is there a command to stop the external hard drive from Doug whatever it is doing?

I hope someone can help as there is an awful lot of things on that hard drive

I presume the external hard drive wasn’t ejected properly when my previous computer broke so it’s just trying to do something and is running the process over and over again

Thanks!

Just run a disk check on it. That has worked in the past for me.

 

[Brian33]

The original iMac was 2016 and it had the latest OS on it (I can’t remember what it was called ? but it was updated)

The iMac I have at the moment is 2013 and has Catalina.

So, if I understand correctly, a Time Machine external drive created by "the latest OS" (presumably Monterey) will not mount on a different machine running Catalina, although the disk sounds like it's spinning, and maybe there's some disk activity.

I don't know this to be true, but it's plausible that changes between Catalina and Monterey in APFS and/or Time Machine could prevent it from mounting. If that guess is true, then it will be readable by your new machine (which will have Monterey on it).

It shows up in disk utility but is greyed out. I tried clicking “mount” but it doesn’t mount.

I also tried to eject it in terminal using “eject disk3” but it failed to eject.
And “unmount disk3” “unmount force disk3”..

So I don’t know what to do.

Is there a command to stop the external hard drive from Doug whatever it is doing?

The reason the unmount comands don't work is that it's not mounted. AFAIK, if the disk (technically, the volume) is not mounted, there should be no changes being made to it. (The exception would be if there were some partitioning or formatting going on, but I would not expect that to be happening "all by itself".)

You could get some technical info by opening Terminal.app and entering diskutil apfs list. You could post the output here. I can't guarantee it'll help, but it will show what's mounted and what's not.

If it were me, I'd probably just power down the external (if it has separate power) or just unplug it from the Mac. I think you'll be OK, but... you could see what others suggest!

 

[macfoofoo]

Open diskutil app, right click on it, run First aid

 

[Fishrrman]

OP:

I realize this doesn't help you NOW, but a bit of advice for the future...
(Here goes the old Fishrrman, like a broken record as usual)

STOP USING time machine for backups.
Instead, use either CarbonCopyCloner or SuperDuper.
Both are FREE to download and use for 30 days.

If you had a cloned backup from either CCC or SD, you WOULD NOT be having the connection problems that you're having now.

Having said that...
Referring again to my post 4 above...
What happens when you press the power on button on YOUR OLD iMAC?
Nothing?
Or... something else?

 

[ThrowerGB]

The original iMac was 2016 and it had the latest OS on it (I can’t remember what it was called ? but it was updated)

The iMac I have at the moment is 2013 and has Catalina.

Sorry, the power on of the iMac? It has an apple logo, loads up and then goes into the login screen

Given that your original iMac was newer (2016) then the one you have at the moment (2013), I'd suspect that there's something about the TimeMachine drive that's not backwards compatible with the older 2013 iMac. My approach would be to test the TimeMachine drive on a newer iMac, preferably 2016 or newer.
If you try this, you might want to Get Info on the TimeMachine drive before setting it up for TimeMachine on the newer iMac. This will help you confirm the health of some aspects of the drive such as mounting, the format, available space, etc. Then I'd try looking at it with Disk Utility to see if it mounts and shows reasonable settings. Don't use First Aid just yet in case that tries to write something to the disk. Instead, try running Restore from the TimeMachine disk to a 2016 or newer iMac. If that works, then things might be in good shape.
In future, when things are working, I think it's best to run TimeMachine set up for two TM disks. That way, if one disk fails, you at least have a second TM disk that's at least the 2nd most recent backup and possibly the most recent.

 

[gilby101]

Just disconnect the TM disk. Don't reconnect until you have a Mac running the same (or later) version of macOS as was on your broken machine. If that was the latest macOS, then will be macOS 12.x (Monterey).

Using an older Mac (with an older macOS) carries a risk of corrupting the backup.

Don't try to repair a disk with a Monterey backup using an older macOS.