How to fix bad thumbnails in Photos on macOS Sierra
Since updating to macOS Sierra my Photos library will show some bad thumbnails that are either completely black or have black “bars” on them. Here is just one example that I managed to screenshot (see: top left photo).
If you come across this issue it is pretty easy to fix.
- Right-click (or, control+click, or two-finger tap) on the photo.
- Choose “Rotate Clockwise” (this will rotate the photo, and regenerate the thumbnail)
- Rick-click on the photo again
- Hold down the Option key
- Choose Rotate Counterclockwise (this will rotate the photo back to its original orientation)
I don’t know what causes these bad thumbnails but at least it is relatively easy to fix them.