For SDXC cards there any way to disable write caching and the annoying "disk not ejected properly" messages?

Xeon5100 wrote:

That has no effect on the warning; in reference to your other question, it does this both with the built-in reader on my Studio Ultra and on a reader connected via USB-C.

And you are saying this after trying it and comparing the results....or it was already set to OFF.

This "hard drive" setting has been known to negatively effect SSD/flash.

Studio has built in SDXC...

—try a different reader

—try a different cable

—try different brand cards

these are all options.

you can file a bug report /submit your Apple Feedback here:  http://www.apple.com/feedback 

As far as I know there is no way to change this behavior. Apple always wants you to follow their procedure for ejecting a drive or card and not just manually removing or you will get that "not ejected properly" message..

Xeon5100 wrote:

I deal with a lot of memory cards for cameras, and for five major OS releases, Apple has required manual ejection of SD cards - which is something required by no other OS or device that uses these cards. And why would I need to manually eject a card that was just formatted? By definition, there is nothing on it.

Is there a command-line solution to kill write caching (if it is even happening) and these warnings on SD media?

When mounted on a computer, these cards are almost always used for read-only file transfers, and the incidence of yanking one out while it is reading is both low and pretty harmless. Whatever application's operation is being interrupted will throw a warning anyway.

Is this through a hub or through the built in SDXC reader...

Look at your Energy Saver Settings

See "Specify sleep and wake settings for a Mac desktop computer"...

Set sleep and wake settings for your Mac - Apple

something similar on a Mac Studio—

Xeon5100 wrote:

This happened with 13 cards from Sandisk, Samsung, and Toshiba. It has happened now with 5 different readers on three different Macs with five different OSes starting with X. (Intel mini, Intel iMac, M1 Ultra Studio, all with their built-in and their external readers). So it's hard to say this is a bug - it's a UI/UX choice that is an artifact of spinning disks that Macs don't even use anymore. I've already reported this to Apple, but that's a black hole.

great information to have included in your original post...