Seeking applescript/automator help w/unmouting disk

[Ben J.]

Hi.
I bought a WD Blue 2.5 2tb SSD the other day, and I put it in a external USB-C enclosure and connected it to my 2018 Mac Mini. All is well, I mesured its read/write speed to about 400mbs, which is fine.

BUT, it turns out that there is a 30mb partition called "AU0039" on it that's impossible to get rid of. I looked around the net, and I see TEN year old posts with people being angry about this thing with WD drives! And, it seems, no solution.

This partition shows up with an old-fashioned CD-ROM icon and contains a "Setup.exe" file and some windows stuff. If you click to eject it, it goes away for a second, and then comes right back. Disk Utilities says it's "Unknown format", it sits outside the APFS container, and when you select it, all options turns to grey. DU can't do anything with it, EXCEPT if I eject it in DU, it stays hidden until I unplug/reconnect the disk or do a restart.

I found this script that people said you could use to make it stay hidden:
tell application "Finder"
activate
try
(eject) / Volumes / AU0039
end try
end tell
But for some reason, it doesn't work here.

If Disk Utilities can do it, I'm thinking it should be possible to make a script that can also, and that I can have in my "Services" menu.

Thanks for any help.

 

[BrianBaughn]

So…in Disk Utility with View>Show All Devices checked you can't select the overall device and erase it?

 

[Ben J.]

Correct.
Once I select it, all options to erase, partition etc turn grey. Buttons and menus.
Also as I said, it sits outside the APFS container of the disk. People say its because it actually sits on a separate chip on the drive.

 

[Ben J.]

So…in Disk Utility with View>Show All Devices checked you can't select the overall device and erase it?

To be presise:
If I select the device and erase it, the APFS container is erased and recreated, while the 30mb "Unknown format" partition is unaffected. Even though it resides on the physical drive I just erased.

 

[BrianBaughn]

Ten year old info on WD drives shouldn't even pertain to your SSD. Have you tried a different method of connecting it to your Mac? What is the model of the housing it's in now?

Is there any information you can derive about the files in the mystery partition?

 

[Ben J.]

Here are examples of what I get from googling:

ð WD SSD "Virtual CD" partition erase - Google Search

www.google.com

Even WD support acnowledges that these partitions are not erasable.

How about you help me with my original question:
How can I make an applescript that simply does what DU does when it ejects the partition and has it stay ejected, something the Finder can't.

 

[BrianBaughn]

The terminal command is

diskutil unmount /dev/disk[x]s[y]

where "disk[x]s[y]" is the device identifier you can find using Disk Utillity.

I'd create an Automator application or other with a "Run Shell Script" and put the Terminal command, by itself, in the shell script section.

You could have the application, if that's what you create, run at login but you might need to put a "Pause" delay before the Run Shell Script so that the external gets properly mounted before the command is run.

 

[Ben J.]

Thanks a lot, Brian.
Exactly what I needed.
I have now created a Automator program that ejects the volume, and it stays ejected. And I'll have it available in "Services" menu. I'll look into having it run at startup later.

Thanks again.
This is a great forum.