External Hard Drive Mounting Problem

[PGB1]

Hi All!
I don't know if this is the correct section for this question, so please forgive me if I missed.

I have a hard drive in a USB enclosure that won't mount anymore.

When I plug it in, the light on the enclosure flashes for as long as I leave it, but it never shows up in Finder or on the Desktop.
If I open Disk Utility, the page says "Loading Disks" for as long as I leave it.

After removing the drive, Disk Utility won't show the remaining (mounted) disks. It stays on Loading Disks. Actually, even closing the application and re-opening it, I get the "Loading Disks" message. I have to re-start the computer to get Disk Utility to act properly. (Without the offending USB drive attached)

I tried Terminal App to mount it the long way. Terminal app's List command shows it is, indeed, mounted.
(Screen Shot is attached. The other drives are the computer's hard drive and a partitioned external that does work. The bad guy drive has an arrow pointing to it.)

Next, I verified the USB port is OK. After that I tried the drive in another enclosure and a known good drive in the USB enclosure. The result told me the drive is the problem, not the enclosure.

First I believed the drive was bad, but Terminal shows that it is mounted, so it can be seen by Terminal.

Do you all know any tricks to get the drive to mount, or is it destined for the recycle bin?

Thanks For Helping!
Paul

 

[MacInWin]

You might try powering down, connecting it, then booting again with it attached. What happens if you try that?

 

[Raz0rEdge]

The 'diskutil list' command does NOT show the mounted drives, but rather detected. There is quite a bit of difference between the two. When a drive is installed or plugged in, the OS does a scan to see what type it is to get the physical parameters, and then is able to determine the number of partitions and type. In this case, it seems that the drive in question is OK enough to provide that much info back to the OS.

Mounting the drive requires data integrity which this cursory scan will not guarantee.

To list the mounted drives, you would use the 'mount' command. You will see 1 line per mount (some of them are physical drives denoted by the /dev/diskXsY nomenclature, while others will be virtual like devfs, map and so on). From your 'diskutil list' you can IDENTIFIER to the mount line and see what the mount point is. External drives always end up on /Volumes/<name of device>.

If the mount isn't happening, then you might have a corrupt partition.

 

[ferrarr]

Is the drive being connected to the Mac, or is it being connected to a hub?

I just noticed with one of my drives which is in a USB 2 exclosure, it's a 2.5", GUID partition, & ExFAT formatted drive, is not showing up, when connected to a powered USB 2 hub, but it is showing up, when directly connected to my Mac Mini.

 

[chscag]

The drive likely has problems. I've had drives show up in Disk Utility (just as Ashwin indicated in his reply) but refuse to mount. I suppose that with some drives you may be able to repair it, but frankly it's not worth the effort and risk losing data especially since new drives are so inexpensive nowadays.

 

[pm-r]

Unmount and disconnect the other working drive while you do your diagnosi with the other goofy one.

Save you and the Mac getting confused. ;-0


- Patrick
======

 

[harryb2448]

As this is an SSD are you using APFS?

If so use the Terminal Command to get a list of drives using the command diskutil apfs list and see if it appears.

 

[PGB1]

Thank You Everyone for teaching me & helping me with this drive problem.

The drive "fixed itself", as explained later. But I sure don't trust it.

Here Are My Step-By-Step Attempts:
You might try powering down, connecting it, then booting again with it attached. What happens if you try that?
No luck, Jake- But a good thing to remember for next time.

Thanks Ashwin for your explanation of the Diskutil command. it clarified things quite well for me.
The Mount command confirmed the drive was not mounted. Mounting from Terminal didn't work unfortunately.

Is the drive being connected to the Mac, or is it being connected to a hub?

Thanks Bob for that tip. Actually, I tried it both ways, just in case the (powered) hub would have some positive effect.
One of my thumb drives acts like you described. It's fine directly connected, but won't be recognized when in a hub.

Unmount and disconnect the other working drive while you do your diagnosi with the other goofy one.
Save you and the Mac getting confused. ;-0

Thanks Patrick! Doing this certainly made my project easier. I do get confused easily. Now what was I doing???

use the Terminal Command to get a list of drives using the command diskutil apfs list and see if it appears.
It's a rotating hard drive, Harry. But that's a good command to keep for future reference (When I get a newer computer. Mine can't use APFS format.)

I tried some other Terminal commands, such as "repairVolume". It showed Error Starting Repair.
EraseDisk didn't work either.

Next I tried "info disk3"
It revealed that there was no file system. At this point, I figured the disk was now blank. I was wrong.

While typing this reply, I had left the drive plugged in to the computer. (Note that since I'm quite dyslexic, I've been typing this for over an hour. And that's why all of my posts have many edits. The disk has been in for about that amount of time.)

I believe the disk wanted to be left alone for a while...
I noticed the enclosure's light stopped blinking. Checking Finder showed the disk was mounted & accessible. The information was still on it and readable.
Before anything went haywire, I used Disk Utility First Aid. It showed no problems. Next I used Disk Utility to erase it.

I've ejected & re-mounted it a few times since the above. The drive seems OK now. (Key word is "Seems")

I'll follow the advice from Chscag: you may be able to repair it, but frankly it's not worth the effort and risk losing data especially since new drives are so inexpensive nowadays.

This drive is (was) used as a second destination for Time Machine in case the first, larger, drive failed.
A trip to Mac-Sales for a new drive and enclosure sounds like a good plan. I'll keep this drive & enclosure for non-critical things, such as sharing a file.

Thanks Again All for helping and for the great education plus advice.

Enjoy Today!
Paul

 

[MacInWin]

Paul, I have a theory on what may have happened. No science, but a theory. I had a drive a while ago that had been a TM backup. I wanted, like you, to reuse the drive so I attached it. It didn't appear. However, I have a dual-screen setup and keep Activity Monitor on one screen so I can see what is going on and I could see a lot of disk activity. I also saw some CPU activity but I don't remember the process name. So I knew something was going on. I let it run for a while and eventually it mounted, the backups were fully visible and the disk activity stopped. So what I think may be happening is that because it was a TM drive, and because the OS knows when a drive is a TM drive (the icon changes, for example), it might have been doing an integrity check on not just the drive, but also the backup. And integrity checking on a TM backup can take a long time because every chain of links needs to be tested. So that's my theory for what happened to you--the drive was being integrity checked AND the TM backup was being integrity checked as well.

In any event, glad you got it sorted.

EDIT: And by the way, subsequent mounts of that drive, even with the TM Backup still there, worked well. TM must somehow mark or store the metadata on the backup to know when it needs to do a full check. (Also theory, I have no evidence that it does that other than the observation of what happened to me.)

 

[pm-r]

(Note that since I'm quite dyslexic, I've been typing this for over an hour.

And congratulations for struggling with your typing and providing an excellent feedback of your situation.

It seems from your's and Jake's experience, that TM could certainly be the cause and something to be aware of. At least for those who use it.


PS: Have you tried using the built-in Dictation to help out with any typing that's probably installed onto your Mac???

Just a thought... In case it might help you and any typing you may have to do.



- Patrick
======

 

[PGB1]

Thank You Jake for your good explanation of what might have happened.
It sounds quite logical, especially since Disk Utility could see the disk, but it was not mounted and because the drive eventually mounted OK.

It is working fine today. I'll still replace it with a larger drive for Time machine. (I did not realize, until this problem arose, that the price of drives has come down so far.) This drive was the original in my MacBook Pro in 2007, so it has performed quite faithfully.

I wonder had I opened System Preferences -Time Machine while the drive was trying to mount if Time Machine would have had a message saying it was doing an integrity (or other) test.
Next time, I'll open that and Activity monitor.

Thank You Patrick for your suggestion of Dictation. It's really amazing.
I experimented with it for a while today and found it fascinating how fast it translates. I'll work with it more today.

Some days I can not compose, but I can read fairly well. On those days, your suggestion will be of great help so I can proof read. On days when I can neither read nor write, I can dictate to Text Edit and proof read later when the "brain switches" are working properly. Then I can paste the text into where ever it belongs. Sure beats waiting for the brain to kick back into gear.

Warning! If I can dictate-to-text, my forum posts will be even longer than the tomes they often become!

Thanks Again Everyone for helping me with this drive problem and for the very good education!
Enjoy This Day!
Paul

 

[pm-r]

@PGB1

Thank You Patrick for your suggestion of Dictation. It's really amazing.

I don't know how well your OS X version of Dictation works, but if you use Google Chrome for browsing and a lot of your text, I have found that the Google Chrome extension plugin Voice In Plus does vast superior dictation. But I am also only using Mavericks.
Unfortunately it's only good for dictation in Google Chrome.
VoiceIn Voice Typing - Chrome Web Store


- Patrick
======

 

[PGB1]

Thanks Patrick. I don't use Chrome, but will try it out. So far, Apple's dictation is working very well & is acceptably fast. (OS X 10.11.6) I understand it uses Apple's Translation Services, so the internet is involved. Considering that, I am really impressed with the speed. (30 Mbps Up & 5 Mbps down).

I have been "torture testing" the problem USB drive.
With a Time Machine backup on it, it has done mostly well, but will occasionally fail to mount. After some time, up to a couple of hours, it will finally mount.
With no Time Machine backup, it never fails to mount right away.
The other Time Machine drive, which is connected by Firewire 800, always mounts.

The above symptoms tend to reasonably confirm Jake's experiences.

I ordered a new drive for Time Machine and a new enclosure for the drive. The drive is just under 3-1/2 times the size of the file selection Time Machine backs up, so I should eventually build up a good supply of previous versions.

The new drive is SSD. I didn't get SSD for the speed, since the USB 2.0 is slow. I got it because no matter the claim of the enclosures, or the setting in System Preferences - Energy for turning off hard drives- any external drive I've ever connected spins all day. They get very hot. Hopefully a SSD will stay cooler and use less energy.

All this attention to Time Machine has taught me one thing that I never realized. When I need a previous version of a file, it is much easier & faster to find it in Time Machine than in my offsite plan. (Although the offsite is not difficult, just 'internet slow'.)

 

[pm-r]

Thanks Patrick. I don't use Chrome, but will try it out. So far, Apple's dictation is working very well & is acceptably fast. (OS X 10.11.6) I understand it uses Apple's Translation Services, so the internet is involved. Considering that, I am really impressed with the speed. (30 Mbps Up & 5 Mbps down).

Apple also provides an option:
Choose whether to use Enhanced Dictation, which lets you use dictation when you're not connected to the Internet.
Use your voice to enter text on your Mac - Apple Support

Some say it seems to work faster.

Try it either way and see which one might be better. I find with enhancement off it's almost so slow it doesn't seem to be working, and there's no feedback to show that it is while one waits. But it is definitely more accurate and it doesn't put capital letters all over the place or join words together.



- Patrick
======

 

[PGB1]

On the first try, Enhanced seemed no faster than without. But when the backup program was using bandwidth, Enhanced was much faster.
As you mentioned, i found accuracy better, especially when it came to jamming words together.
Thanks For The Tip!
Paul