USB drive ejected improperly, leaves temp files, won't find ever again.

[nadia p.]

I've run into this issue more and more with later versions of macOS which requires me to reinstall macOS to resolve it... there's got to be a better way.

ISSUE: When a non-powered 2.5" USB-A external hard disk drive is attached to MacBook Pro computer (macOS 10.13.6), it mounts the USB drive's file system just fine, then inadvertently the USB-A cable is moved just enough to cause the failure of the USB-A connection for a split second. A macOS notification pops up informing us that the drive has been ejected improperly.

After this happens when the USB-A cable is reinserted securely sometimes macOS will locate the device and remount it, other times, depending on maOS's decided state, it will never see that USB-A drive again until one installs a fresh copy of macOS. Only then does it see the drive as if nothing ever happened.

QUESTION: There has to be some sort of temporary file(s) created that macOS is keeping track of, does anyone know where these files are located and what there names are?


TROUBLESHOOTING: Here are the various steps or procedures I've already attempted to help validate that macOS is the issue not the external USB-A drive.

1. Attach the same USB-A drive any other Apple computer, all of which mount it's file system perfectly.
2. I've tried booting into Safe Mode to attempt to clear all temporary files, doesn't resolve the situation.
3. I've tried both USB-A ports on the MacBook Pro that has encountered this issue without success.
4. I've attempted to locate the USB-A drive via Disk Utility and Terminal through various commands, doesn't see it.
5. I've looked around /private/tmp and can't see any files that seem to be associated with mounting a USB drive.
6. Both USB-A ports on the MacBook Pro see every other USB-A connection, including other USB-A drives (thumb and hard disk) accept the one that has encountered the improper ejection issue.
7. I've created a new account and attempted to login as the new user, then mount the USB-A drive, no luck.
8. Powered down, unplug power, wait 15 min, then reset each NVRAM, PRAM and SMC independently, no luck.
9. Swapped the USB-A cable, no luck.
10. Boot while holding OPTION key with USB-A drive connected, no luck.
11. Boot to recovery then insert USB-A drive, not found.
12. Boot using USB install thumb drive, then insert USB-A hard drive which it finds it so the port can see it.
13. If a fresh install of macOS is installed then the USB-A is found every time, until it's ejected improperly by accident again.

How does one resolve Apple's problems? We never use to have issues like these in earlier macOS (rather OS X) installations. There's got to be a better way to resolve this without having to reinstall macOS to remove their issues. One would think this should be rather simple to resolve.

 

[Fishrrman]

First, try A DIFFERENT USB cable for that drive.
Sometimes that's all that's needed.

Next...
If the drive accidentally dismounts, and then won't mount back up when you reconnect it, try this:

a. power down the Mac, all the way off
b. disconnect the drive
c. power on the Mac, let it get to the finder
d. NOW, re-connect the drive, and... just wait (give it a few minutes)
e. The finder may try to "repair" the drive to get it mounted again.
No promises that this will work, but worth a try.

 

[nadia p.]

First, try A DIFFERENT USB cable for that drive.
Sometimes that's all that's needed.

Next...
If the drive accidentally dismounts, and then won't mount back up when you reconnect it, try this:

a. power down the Mac, all the way off
b. disconnect the drive
c. power on the Mac, let it get to the finder
d. NOW, re-connect the drive, and... just wait (give it a few minutes)
e. The finder may try to "repair" the drive to get it mounted again.
No promises that this will work, but worth a try.

Hi Fishrrman, thanks for your reply and suggestions. My apologies, I didn't include these steps which you've noted in the list of things I've already tried.

What I've found is macOS does some sort of operations to discover the USB-A external drive since it seems to hunt for some startup files or some sort of disk IO/activity then stops and does nothing.

I've been able to reproduce this multiple times on any MacBook Pro and Mac Pro and narrowed it down to something macOS is doing. It's not hardware related nor are there temp files written to the USB-A external drive since I've examined that after each occurance (improper eject) during our testing.

 

[jagan]

What file system is on the drive?
Also: try to see if it shows up "greyed out" in Disk Utility", and press "Mount".