Same issue. Have tested on Windows PC and on Mac, and in multiple browsers, and have tried clearing cache. All to no avail. Box Status shows all green, but clearly something is wrong. I am nowhere near storage limits. FWIW, in folder view, "Details" shows this error: There was an error loading metadata.

"Can someone please help update ASAP??" --- YES PLEASE!

Also getting intermittent NETWORK ERROR messages if I try to download files to work locally.

Update: In any given folder, some thumbnails are now loading and others are not.

Note: These are all JPEGs.

...but most are not loading.

i'm still not able to see any previews :( 

Try again now. Clear your browser cache and you may find it works. I haven't checked every folder, but what I have checked seems to be working again now.

working now! thanks for the update brian!