I'm running both PM6.0 build 3954 and the most recent beta of PM+
MacOS 10.13.6
When reviewing a contact sheet for a folder of images, all thumbnails have a black border on top and bottom and will not double click to open. Other folders on the same drive work as expected without borders. I've reviewed the files from Finder and the files are there and I can open with a variety of photo applications. I've been using PM for years and I can't recall running into this before. Searched the forums but no joy from that.
I've closed and reopened PM to no avail. I've attempted Refresh and Rescan to no avail as well. So now I'm out of ideas as to why the images will not open from PM