Recent update of the desktop app not allowing me to see .clip thumbnails in File Explorer.

Wanted to say that I'm having this exact same problem with thumbnails as of last week or so - only Clip Studio files aren't showing the thumbnails in any synced folder. When the Dropbox app is closed (as suggested above), and I remove the file from the folder, then put it back in, it's visible as a thumbnail, with blue syncing logo, but as soon as the app is reopened and the file is synced, the thumbnail turns back into an icon instead. This makes navigating work files quite difficult.

Also, it seems the recent build broke saving (potentially only larger) Clip Studio files in synced folders within Dropbox as well. Dropbox attempts to save them before the files themselves are finished saving locally, and leaves behind a corrupted file, which breaks the Clip Studio file. You can "save as" an entirely new file, as the corruption happens within Dropbox, which will then sync correctly, but the leftover corrupted file remains and has to be deleted. And if you don't remember to "save as" a new file, you'll completely lose it.

I've installed the latest build you linked and it did not fix either issue. The only solution for now is to completely disable syncing, then re-enable syncing when not working.