Macbook Pro sees external drives but doesn't mount or show them in the disk utility.

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My Macbook Pro, OS 10.14.2 doesn't show external drives but knows when they are connected.

In "About this Mac" > "Storage" it shows the disks with the total size of the disk but not the amount of data on it or available. It names the disks "External 2TB USB Disk"

The Finder doesn't see the drives. I have selected to show the external drives in the finder preferences.

The Disk Utility only shows the Macintosh HD

It's the same for both USB ports on my 2014 Macbook Pro, they are working with other devices, the computer runs smooth.
3 different USB cables were tested.
The disks are from different brands (Toshiba and WD)
The disks run when connected, were used on this computer before, although it might have been 2 yrs since the last use. They never ran on any other computer.

I hope I am overlooking something simple;)
 
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I did a back up to an external hard drive yesterday and when I came to dismount, couldn't see it in Finder. Eventually discovered it on the Desktop. Tried it again now - same thing.

Looked in Finder Preferences and saw that external discs had been deselected - no idea how so I changed it back.
 
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I did a back up to an external hard drive yesterday and when I came to dismount, couldn't see it in Finder. Eventually discovered it on the Desktop. Tried it again now - same thing.

Looked in Finder Preferences and saw that external discs had been deselected - no idea how so I changed it back.

Unfortunately not the case here. Since the disks are formatted on long while ago (on a mac still) I think that might cause the problems. I am going to try my old macbook that hasn't been updated for 4 years and see if the disks works on that one. It shows how relative backing up files is;)
 
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If they're not showing up in Disk Utility, that doesn't sound good. Have you rebooted your MBP and tried connecting one of these drives again?

If that doesn't work, I might try booting in Safe Mode (hold SHIFT key after startup tone and release when you see Apple logo)

If that doesn't work, try booting into Recovery Mode (hold CMD + R after startup tone until you see the Utilities window) - open Disk Utility there and see if the drives will show up.
 
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Thanks Usaora, I tried the rebooting but not the Safe Mode yet.

On an old MBP that still had OS Mountain Lion on it the drives both showed like normal. I reformatted them and after that they showed on the MBP with OS Mojave (10.14.2) I reformatted them again on the Mojave MBP to "Mac OS Extended (Journaled)". The APFS format types didn't show in the Disk Utility. And they seemed to work after that, they only randomly dismount from time to time while transfering files. Tried this on both USB ports and used different cables, so that feels a bit unstable / insecure for a backup drive.
 
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Just out of interest, is the drive showing on the desktop? Similarly, switch off showing external drives in finder preferences and see if it appears on the desktop.

Are you able to connect with a different cable or is one end fixed in the drive? Also make sure usb ports are clean - a poof with a lens puffer.
 
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Just out of interest, is the drive showing on the desktop? Similarly, switch off showing external drives in finder preferences and see if it appears on the desktop.

Are you able to connect with a different cable or is one end fixed in the drive? Also make sure usb ports are clean - a poof with a lens puffer.

They show on the desktop, it seems to work close to normal now they are newly formatted. I agree that the sudden dismounting is probably a cable / connection thing. A little strange since that wasn't the original problem and I've used different ports / cables. It's solved 90% now, so that's decent;) Thanks for the help!
 
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It seems to be a strange software issue. I am back at the start. Even with a 3rd new external drive. After the formatting, the two disks already owned seemed to work for one or two sessions. I moved files onto them and all was fine. Same with the new drive.

Now one by one they stopped working.
They show on the desktop as an icon as soon as they are connected.
With an external drive connected Finder will not open, it will not even show "Finder" with its menus in the top bar next to the apple logo.
Uploading an image here with the web interface was not possible while the external drive was connected. (Probably a Finder thing.)

The Disk Utilily gives a spinning wheel.
Screenshot 2019-01-27 at 12.41.34.png

The "About This Mac" > "Storage" screen looks strange.
Only "Backup 1" is connected. Yet it shows drive "backup 3" twice while it isn't connected, it also says that the unconnected drive with that name is 2TB while it is only 1TB
Screenshot 2019-01-27 at 13.00.52.png

I am a little afraid for my data since backing up, even on a new 3rd drive gives issues:Oops:
 
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Sounds like the drives are either going to sleep, or turning off, on their own, so when you try to find them, they are not there. The interface in them is not responding to the OS, or to Disk Utility and Finder.

I think the drives are toast. At this point, I'd take everything I can off of them while you can see them and replace them. Right now drives are cheap.

One final thought: I had some WD drives that kept disconnecting. Took one drive apart and put the disk itself into a new enclosure and it worked perfectly. Did the same with two others and now have three functioning drives. The issue was with the USB interface in the drive enclosure, not the drive itself. After you pull the data off the drives and replace them, you can try that if you want to see if you can rescue the drives at all.
 
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Time to try NVRAM and SMC resets.

NVRAM - https://support.apple.com/en-us/HT204063.
SMC - https://support.apple.com/en-us/HT201295.


Bob -

Sent from my iPad using Mac-Forums

Thanks!

After the NVRAM reset the Disk Utility showed the drives.

But reformatting to "MAC OS EXtended (Journaled)" (The APFS formats are not available here) the disks gave this error:
"Unable to unmount disk"

After the SMC reset I was able to reformat the disks. .

First Aid failed and suggested to run in recovery mode with 2 of the 3 disks. (Including the 1 day old disk)

First Aid in Recovery mode gave this error:
macosjourinrecover.jpg

In recovery mode the APFS options are available for reformatting so I tried that. With the APFS format type I ran the First Aid again and both disks showed:
APFSrecov.jpg

So it seems fixed. I am not sure why the format type played a role but it seems to be the case. I sure needed the NVRAM and SMC reset in order to get things going.




Edit: I celebrated to early, it seems the OS before the NVRAM / SMC resets somehow killed the disks. I just tried to copy 72GB to one of the disks and it stopped at 42GB while still connected. It's strange since all 3 disks have similar problems, one disk is 1 day old. USB disks and SD cards work fine. It might be something MacInWin suggested, with the disks randomly going to 'sleep' (although I can still hear them running when unrsponsive.)
 
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I sure needed the NVRAM and SMC reset in order to get things going.



Give that ferrarr Bob guy his due credit for the suggestion!! Maybe he can wave his magic wand and suggest a new solution for the last problems...





- Patrick
======
 
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Are you using a powered USB hub, or directly connecting the drives to the MBP? Have you tried with only one drive connected at a time? I have a feeling, the USB ports are not supplying enough power to the devices?

Another thing you can try, is to set up a new macOS user account, and see if the same thing happens?
 
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Are you using a powered USB hub, or directly connecting the drives to the MBP? Have you tried with only one drive connected at a time? I have a feeling, the USB ports are not supplying enough power to the devices?

Another thing you can try, is to set up a new macOS user account, and see if the same thing happens?

Revieved a powered USB hub today, tested it extensively and all disks work without trouble! Thank you Ferrarr;)
 

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