I've got it to work on C drive, but I have a lot of files on an external (E) drive. It's not working for that. Is there some way it can work for external hard drives too?
Ah we're getting somewhere! SaiThumbs might not be handling the external drive properly. Did it use to work for your external drive before and now it isn't? Maybe try running Disk Cleanup and clear your thumbnails cache like so:
