Backup Disk Not Found

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Level 1

23 points

Backup Disk Not Found

My friend's TimeMachine can't find her back-up drive ("Disk not found"). We turned the computer off and confirmed the connections are good. Didn't help. We used Disk Utility and confirmed the back-up disk was readable. It was. We had Disk Utility do a "First Aid" check on the backup disk, and it checked out good. But TimeMachine just can't see it -- No Disk can be seen by TimeMachine. We checked preferences, and all the obvious stuff. I thought her passport external disk must have died -- but Disk Utility says it is fine.

Any ideas?

My friend has an iMac 21.5", Mid 2011, and is running OS 10.11.6 El Capitan.

Posted on Oct 28, 2020 12:18 PM

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Answer 1

Eau Rouge

Level 8

42,602 points

Oct 28, 2020 4:49 PM in response to RFeather

Is the Time Machine drive connected directly to the iMac.

If it is using a USB hub it should be a powered USB hub.

System Preferences> Time Machine> Select Disk is the drive to be used for Time Machine selected.

How was this external disk formatted, for Time Machine it must be Mac OS Extended (Journaled)

on a GUID partition map.

Can the drive be seen on the Desktop (Finder> Preferences> General> Show external disks on the Desktop,

mae sure that is checked. Can you open the disk and examine its contents.

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Answer 2

RFeather Author

Level 1

23 points

Oct 28, 2020 6:30 PM in response to Eau Rouge

Yes, the drive is connected directly to the computer. A USB hub is not being used. Disk Utility has no trouble seeing it. I will double check to make sure it is selected. I'm not sure how the external drive was formated, but it has been working for years. First backup was ?? several years ago, and last backup was October 15, 2020, so it must have been formated correctly. I'll check on the last two suggestions.

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Answer 3

Eau Rouge

Level 8

42,602 points

Oct 28, 2020 6:39 PM in response to RFeather

Disk Utility is simply acknowledging its presence, First Aid only checks the directory of the disk not the disk itself.

If you really want to check the disks health download this app, https://binaryfruit.com/drivedx

there is a free trial period.

Highlight the disks icon on the Desktop press Command-i to get the info panel up under General it will tell you

what format it is.

If it had been working for years then it will have been formatted correctly.

Is the disk making any unusual noises, clicking or squeaking, suggesting the heads may be stuck.

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Answer 4

RFeather Author

Level 1

23 points

Oct 28, 2020 9:45 PM in response to Eau Rouge

Thank you for your suggestions. I talked to my friend again (by phone, so it's hard to convey what, to her, is complicated directions. We had her plug the backup drive directly into the computer, not a hub.

She can not see her external backup drive mounted on her desktop. She can not see it under list of devices in the sidebar of a window. When we went to TimeMachine preferences, chose "select disk", she could see her disk listed there. When she clicked on it, her only option was "remove disk". She said there was no "use disk" option. So we chose remove. It disappeared, and now it won't reappear in the list. Even after she unpluged and repluged it in, rebooted, etc, her back up disk will not reappear as an option in Time Machine preferences options.

So I said screw it -- go to Staples and buy a new hard drive, and we'll see if we can get a new one to work. But keep the receipt in case it doesn't.

Again, thanks for your suggestions. If a new hard drive works, I'll let you know. If it doesn't, I'll let you know that too.

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