It appears that all my thumbnails disappear after a time, but strangely at different times. First the USB attached to the NAS (usually within 10 mins of working with the drive), then the NAS (can take up to 30 mins, but as little as 15), and at about the same time, every other directory on my...
From a fresh start up of the computer, I can get my thumbnails to generate any where on my computer, the NAS, or the USB attached to the NAS. However, after a short period (not specific, can be 5 mins or 30 mins), the USB drive attached to the NAS will no longer generate thumbnails, however...