Black Thumbnails

Issue: When using Enhanced Thumbnails, some PDF thumbnails show up as black squares or don’t show up at all.

Solution: There’s a setting you can use to fix PDF thumbnails that aren’t generating correctly. Go to the "Tools" menu > "Settings" and select "Manage Files" on the left. Now select the option called "Use Alternate PDF Thumbnailing" and click OK.

You may have to purge your old thumbnails to get rid of the black ones. Do this from the "Files" button above the list of files > "Clear Thumbnail Storage".