User profile for user: SteveSWall
SteveSWall Author
User level: Level 1
17 points

Cannot unmount USB drive in one user account, but can in another. What's next, troubleshooting-wise?

Sanity check. In my main user account, I cannot unmount one of my three external USB drives. I'm doing it solely for my periodic Disk Utility maintenance routine. The other 2 drives worked fine with DU. Disk Util fails on the third drive saying it cannot unmount the drive (it's "in use by one or more applications"). I am guessing there is some background task running on/with this drive in my main user account and the task is not yet complete (or is designed to never complete?)? I have my Music (formerly known as iTunes) library on this drive (although Music/iTunes is not open/running - I always Quit everything before running DU, including this time).


If I log in to another user account, I can run DU just fine on this drive (where no application is pointing to the drive's files, I guess). I am running Catalina 10.15.7 on an iMac 2017 with all the latest updates.


Two questions:

1) Assuming it is some background task (which it may not be?), is there a way to look up or view what task might be running and using this drive? I assume Activity Monitor would be one way - but I don't know how to use it well enough to see which Activity might be traversing to the USB drive. Any other methods?


2) What else could cause my unmount trouble? In other words, what should my next troubleshooting step be?


Thanks in advance!

iMac 27″ 5K, macOS 10.15

Posted on Mar 26, 2021 1:24 PM

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User profile for user: steve626
steve626
User level: Level 6
13,953 points

Mar 26, 2021 7:08 PM in response to SteveSWall

What else is the drive used for? Do you have files for Adobe Lightroom there? Lightroom has some background processes that run after quitting the program. Based on Old Toad's comment, I'd guess that various Adobe programs do some housekeeping in the background, sometimes, accessing files or scratch space. I know Lightroom does as my daughter encounters this and it is always Lightroom that causes it.


What about Photos and the Photos Library? There are background processes (photolibraryd and photoanalysisd among them) that sometimes run even when Photos is not running.


As an experiment, try restarting your Mac. Can you eject the disk after it mounts after a restart, before you start any programs?


Look in Users and Groups to see what your login items are for your account, versus the other account.


Do you have any security, anti-virus, or other "cleaning" or monitoring software that you have installed? Do you have automatic backups to cloud services?


If none of the above helps, you might consider running Etrecheck and posting the results here, someone may find something you have installed that could be causing this.

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User profile for user: Old Toad
Old Toad
User level: Level 10
215,760 points

Apr 18, 2021 10:15 AM in response to SteveSWall

The report indicates that these items are running in the background:

[Running] Audio Hijack 3 Schedule Helper (Rogue Amoeba Software, LLC - installed 2020-11-09)
[Running] com.rogueamoeba.aceagent.plist (Rogue Amoeba Software, LLC - installed 2021-03-05)
[Running] com.expressvpn.ExpressVPN.agent.plist (ExprsVPN LLC - installed 2019-03-16)


With the iTunes library on the EHD could the Rojuge Amoeba apps be involved in the problem. Uninstall them according to the developer's instructions and see.


Regarding the VPN read the following; Unless you're using a true VPN tunnel, such as between you and your employer's or bank's servers, they are useless. Public VPN's are anything but private.  If you're using it to access movies in another country then set it up to not run in the background all the time and only when you need it.

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User profile for user: Old Toad
Old Toad
User level: Level 10
215,760 points

Apr 17, 2021 3:18 PM in response to SteveSWall

I don't see any of the usual suspects in the report.


I'd uninstall all items in then System/Users & Groups/Login Items and run for a bit to see if that makes any difference. If it does add the items back one at a time and test.


I also noticed this:
  [Running] com.rogueamoeba.aceagent.plist (Rogue Amoeba Software, LLC - installed 2021-03-05)

Rebooting more frequently will clear out system and app swap files, temp cache files, and generally help improve general overall performance on the Mac.


You also have a VPN installed. Unless you're using a true VPN tunnel, such as between you and your employer's or bank's servers, they are useless. Just some food for thought.

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User profile for user: SteveSWall
SteveSWall Author
User level: Level 1
17 points

Apr 17, 2021 1:13 PM in response to steve626

OK, sorry for the long delay. (Life...) Thanks for the replies & suggestions!


After a complete Shut Down and power up, I successfully ran Disk Util (before running any apps) on the troubled external USB drive. Great news! Thanks Old Toad! PROBLEM SOLVED! However, I still don't know why I was having this problem or what was causing it. It seems to have fixed itself? But I'll take it!


Suggestions welcomed. Although my problem is solved, my original two questions remain unanswered: 1) How do I easily find Apps that may be running background tasks on this external drive? 2) If not background tasks, what else could have been causing my unmount trouble? To answer #1 I have been running potential culprit apps, then re-running DU until it fails; but no go so far. This is tedious.




More extra credit details about my failed methods, so far... Even after I ran the Applications I thought were the possible cause (iTunes/Music 1.0..6.10; JRiver Media Center 27), then Quit them, I can still successfully run DU on this drive. A great thing.


[I do not have Adobe products (Photoshop or Lightroom) or extra photo libraries on this drive. Thanks for the ideas, so it's not these.]


The only thing I had in Users & Groups under Login Items is Audio Hijack 3 Schedule Helper - so that hasn't changed and is not suspect. I don't think? Hmm. I have run it (Audio Hijack) and DU still succeeds afterward.


I thought it may have been Tidal (which searches everywhere for music files in the background) but I have this feature turned off. And I can run it and then successfully run DU.


While trying different things, I was able to have DU fail, but I was not carefully running DU each time after each thing I played with. But I'll keep trying this to see if I can find the cause. There's gotta be a better way?


I had forgotten about Etrecheck! A great thing! Thanks for the reminder! But it didn't find anything out of ordinary that points toward an "unmount" culprit.


THANKS AGAIN! If I find a cause, I'll post it.

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User profile for user: SteveSWall
SteveSWall Author
User level: Level 1
17 points

Apr 17, 2021 4:50 PM in response to Old Toad

Hmm. I posted a second Etrecheck file from when my machine could successfully unmount and run Dick Util. Here it is again, just in case. I suspect it has the same content under System/Users & Groups/Login - so perhaps this rules this App out as a culprit. But agreed, rebooting more often than my once a week, or whatever is a good thing.


I use a VPN because I'm in a foreign country and log in to my various US accounts for streaming movies, etc. I have not heard that I can do this without a VPN - so how are VPNs useless? (I know a new topic, so never mind. : )

2nd Etrecheck with happy unmountable USB drive.


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Cannot unmount USB drive in one user account, but can in another. What's next, troubleshooting-wise?

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