Disk Utility First Aid: Unable to unmount volume for repair. : (-69673)

I consistently have a similar issue with First Aid not wanting to unmount when run after doing a backup to an external disk. It appears that something is not reset after finishing the backup step.

A solution that seems to work in 12.3.1 is to relaunch Finder before running First Aid. Also, as noted first running First Aid on a higher level (the media or, in my case, the APFS container) also has worked in the past, but not consistently.

Make a backup of everything on that drive. What you see is not normal behavior.

How is the external drive formatted? HFS+, APFS, something else?

Have you installed WD utilities or any other third party disk management tools? Those have been known to conflict with the Mac OS tools (e.g. Disk Utility).

Do you have any other system enhancement tools, like cleaner programs (Clean My Mac), non-Apple security tools, anti-virus utilities installed?

Have you booted into safe mode, that requires holding the shift key down when rebooting, this can take 10 minutes or even more. When it boots you should see Safe Boot in red on the screen. Then try the operation on the disk in Disk Utility?

Q - " I'm using Mac OS Monterey 12.3.1 "

A - Current version is Monterey 12.4 and worth updating as this one does keep the computer up to date, brings some bug and security updates too.

Q - " I’ve JUST installed the WD utilities "

A - macOS is very capable of managing external drives without the Interference from Third Party software which is often times is buggy and does introduce other type of issues

Sorry, have dissected all the Posting in this question.

Do not see a specific mention anywhere by anyone of running 12.4

To quote the Owner of this question " I'm using Mac OS Monterey 12.3.1 and a Western Digital My Passport Ultra for Mac."

So, based on suppled information in the question - it would reasonable to conclude the computer was running 12.3.1

Yes, one may have since updated to version 12.4 subsequently but that information was and is not disclosed anywhere

As for macOS managing external drives - having allowed OS X 10.4 Tiger ( Released April 29, 2005 ) through to and including macOS 12.4 Monterey ( Released October 25, 2021 ) manage every single External Drive and has always worked as expected.

EDITED

I sense there might be an Other Agenda at play.

Best I remove myself from this question and offer a Good Luck with this computer issue

Understand, we are all working Remotely from all around the world. 

Therefore, we do not have the On-Hands experience the User ( you ) has with this computer.

Reliable , accurate, details and context will really help to pinpoint a possible solution.

That is the responsibility of the User to provide this crucial information.

Other wise most everything is Guess Work

some of us who attempt upgrade will be cancelled due to unsupported mac

black screen

and all biz footprint gone?

i dont feel lucky

this stuff should have been nailed ten years ago

stiull cannot connect my nrand new extrenal hard drive

THANSK APPLE

ok if appl can delete my last reply i dont mind

developers are hardened by loose unqualified software in the open source field

being an appl developer Im committed to macbook development

and have a point when we deserve better hardware connectivity

solution... leave the external hard drive in and go have a 1-2 hour coffee

plug in another one to add to the software case logic for usb connectivity

eventually it will show up

then run first aid

this is on a mid 2015 macbook running big sur

and I found it is safe to upgrade to Monterey and I would feel better now they are addressing these issues causing developer's to spend hours on I spent 3 hours yesterday wrestling with my external seagate and 1 this morning and it booted after I took a long walk away from my desk

so the filed is apples to take I ditched windows 3 yrs ago after being a years long microsoft consultant on windows

only to find gates has his laptops emitting plasma energy now setting entire homes ablaze with plasma on every wall socket and appliance or light bulb anything electric

apple macbooks do not do this

so I encourage apple to continue tightening up their ship they will own the field eventually

and the windows game has already harmed itself

be nice to see a new face on macbook OS UI that beats windows down for navigation speed

the future is yours if you want it

and thats coming from a 20+ yr consultant in R&D

thanks for your diligence and commitment to the best

keep america the best

made in usa