"items since last import"

I am experiencing exactly the same symptoms, in a basically identical scenario.  This started after a Windows update within the last few weeks (April 2020).

I am having the same problem and just reported via Feedback Hub.  This is awful.  Mine is even shutting down when I go in and select individual photo to import.  UGH.

Anyway to get directly to Microsoft for a repair???

I followed the advice and reported it to MS via their Feedback Hub app. I think the more people do this the better. I've not had any feedback from this yet but hoping it's making it's way to the right people for action.

On second thoughts I might hold fire on trying to fix it myself. If it's a wider problem then maybe Windows will issue their own fix?

I use a camera for most of my photos.  I was able to keep all photos on the scan disk, and each time I took new photos the system settings allowed me to only import the items since the last import.  Now that isn't an option, continues to lock up.  I need to clear my disk each day and load the photos from that day, delete all photos from the scan disk and do the same thing tomorrow.