If notification was|is the issue it seems (maybe just to me) that you could you use any number of standard api calls to provide notification. FindFirstChangeNotification, ReadDirectoryChangesW and FileSystemWatcher come to mind and if you used them with the twain directory calls you’d know where to look, but glad to hear you found a solution and if you’re only trying to support one device their sdk may be a better long term solution. God knows I wouldn’t use twain if I didn’t have to.
Cheers,