External SSD unable to detect after restart

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External SSD unable to detect after restart

I’ve been using my MyPassport external 1TB SSD for almost a year without any issues, but after a recent restart, it stopped showing up. I was working in Pro Tools (a Digital Audio Workstation) when a strange problem occurred. While I could still access my files through Pro Tools, when I checked in Finder, a folder containing nearly 200GB of data was missing. When I looked at the folder’s info, it showed 0 KB of data.

I decided to close Pro Tools and try to unmount the SSD, but I kept getting an error saying the drive couldn’t be unmounted because some program was using the data, even though nothing else was open. I then restarted my MacBook Pro (2018, running macOS Catalina), but it got stuck on the desktop screen with no clickable options, just the background image. I had to force shutdown using the power button.

After restarting, the SSD no longer appeared. I checked Disk Utility, and instead of my SSD, I saw two oddly named volumes: one called something like “AppleAPFS” and the other named “disk2s2,” which was greyed out. When I ran First Aid on the first one, it said the partition operation failed. The second one showed a green checkmark after running First Aid, but nothing changed.

I’ve tried different cables, plugging the SSD into a Windows PC (where it also wasn’t detected), and resetting both the NVRAM and SMC on my Mac, but nothing has worked. I really don’t want to lose almost 1TB of data on the SSD. What are my options for recovering it?

MacBook Pro 15″, macOS 11.7

Posted on Oct 3, 2024 12:59 PM

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Answer 1

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HWTech

Community+ 2026

Level 9

70,412 points

Oct 5, 2024 2:31 PM in response to elonmerker

Within Disk Utility click "View" and select "Show All Devices" so that the physical SSD and hidden APFS Container appears on the left pane of Disk Utility. Start with running First Aid on the physical drive which will be the item with the name or make & model of the external drive. Next run First Aid on the APFS Container since that will automatically run First Aid on all APFS volumes within that Container.

Even if First Aid says everything is "Ok", click "Show Details" and scroll through the report to look for any warnings or errors. If any are listed, then run First Aid again until they are gone. If after several attempts the errors remain, then you will need to erase the whole physical drive & restore the data from a backup. Of course this assumes the drive is healthy. FYI, the First Aid summary is known to lie (personal experience).

I'm a bit concerned about the "partition operation failed" error.

FYI, Windows does not understand any Apple file systems so it is not surprising that Windows File Explorer does not detect anything. You would need to launch Windows Disk Management app in order to actually see the physical drive. However, if the drive is using any Apple file systems, then do not let Windows perform any scan or repair functions on the drive or you may lose all the data on the drive. You should at least see the physical drive appear and see an unknown partition & file system displayed.

I hope you have a good backup of this external drive.

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Answer 2

elonmerker Author

Level 1

4 points

Oct 5, 2024 2:56 PM in response to HWTech

Thank you for your response! I tried many things including all terminal commands that I saw online and I was able to delete the corrupted partition. Nevertheless, it somehow effected the entire disk so I had to erase the entire disk. But I was able to extract almost %90 of my data through disk drill. Now I’ve been trying to reconstruct the restored files and downlod thw missing ones again..

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Answer 3

Oct 5, 2024 4:46 PM in response to elonmerker

Disk Drill is old technology and is NOT adequate to cover everything on your drives.

If you do not have a recent local, disk-based backup, your computer is like a ticking Time bomb. You are only one disk failure, one crazy software, or one "oops" away from losing EVERYTHING! Drives do not last forever. It is not a question of IF it will fail, only WHEN it will fail. In addition, you never know when crazy software or Pilot Error throws away far more than you intended.

If you are using another direct-to-disk backup method that you prefer, and you currently have a recent disk-based backup, that is great. If not, you should consider using Built-in Time Machine. Take steps to acquire an external drive as soon as possible. If you buy one, a drive 2 to 3 times or larger than your boot drive is preferable for long term trouble-free operation. Do not pay extra for a drive that is fast. (You can get by for a while with a "found" smaller drive if necessary, but it will eventually become annoying).

Attach your external drive and use

System preferences > Time machine ...

... to turn on Time Machine and specify what drive to store your Backups on. It may ask to initialize the new drive, and that is as expected. APFS format is default format if running MacOS 11 Big Sur or later.

Time machine works quietly and automatically in the background, without interrupting your regular work, and only saves the incremental changes (after the first full backup). Time machine backs up every connected drive that is in a Mac compatible format. it can not back up Windows format drives.

Time Machine's "claim to fame" is that it is the backup that gets done. It does not ruin performance of the rest of the computer while doing its backup operations. You do not have to set aside a "Special Time" when you only do backups. When you need it, your Time machine Backup is much more likely to be there.

How to use Time Machine to Backup or Restore your Mac:

Back up your Mac with Time Machine - Apple Support

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External SSD unable to detect after restart

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