i was experiencing something very strange when trying to upload images and i think i may have found the issue.
basically when uploading images from the main site (multisite) they would say "complete" but would not say "crunching" (or whatever else) and there would be no preview image in the media library and also the images would not show in pages.
the last thing i installed was humming bird and defender.
so i checked the htaccess and deleted the humming bird code which seems to be added by clicking "enable caching".
after this the media upload, library preview and images in pages worked fine.
my site actually seemed quicker when i deactivated the plugin but i guess that may be another question for another day.
also by disabling it from dashboard does not seem to help or remove the code from htaccess unless i manually delete via FTP.
support access is granted if you want to take a look and its experimental so feel free "to do your thing" :slight_smile:
can you confirm if this indeed can cause issues with the media library ?