MMI screen shot?
 

Has anyone found out how to make the 2018 MMI save a screen shot to SD card? One dealer rep says it was covered in training, but didn't recall how to do it.

I believe you need need to code it to be turned on.
I may have turned this on last year so next time I am in the car I will try it and see what happens.

https://audiwiki.bitt-c.at/index.php/Screenshots
Screenshots are created using the following key combination: NAV / MAP (or CAR) + Press the rotary switch. First press and hold down NAV / MAP (or CAR), then additionally press the rotary pushbutton and keep both buttons pressed for approx. 3-4 seconds.
As confirmation, the screen will shortly "light up".
The images are stored internally in the MMI.
You can take 50 screenshots. Then the oldest ones are deleted

Where do you view the stored screenshots?

Thanks Just tested, and it works, but then you need to copy to SD card 1
Translated from the German site:
"For export via VCP:

Open Stg-5F-> Basic Settings-> 605 Infotainment Recorder-> Select Card Reader-> Start
Then wait about 2 to 3 minutes.
Then the SD card can be removed.
On the SD card are the screenshots in the folder nn_Export_YYYYMMDD_HHMMSS (for example, 01_Export_20170329_210850), there in the subfolder "MMXcore"

You can do this with VCDS. Open controller 5F, Basic Settings, drop down to Infotainment Recorder. You get two choices, erase, and save. Select Save, Go, and then wait several minutes until it says it's done. It saved to SD card 1.
It saves the images, along with around 300 other small files of status info. Not as easy as it was on my 06 A3, where it simply saved the images to SD card when you hit the key sequence.