I've seen a few posts on this, but no ways to fix the issue. When I import a photo into Photos from my iPhone SE, the photos show up as red rectangles. When I click on the top-right "Live" button, the live photo will show. When it stops, it goes back to red.
Strangely, on a few of the photos, I have been able to successfully duplicate them with the "duplicate as still image" option. For some of the photos, this still produces a red rectangle.
This must be some sort of bug with Live Photos.
I have a 2009 Mac Pro running High Sierra, 10.13.6, with a Radeon RX 580 8192 MB graphics. I'm using the MacOS Graphics Driver.
Anyone have any helpful information? If not, I guess I'll figure out how to turn off Live Photos on my Iphone…