It looks like UltraCompare does not yet support virtual folders. Devices with Android 4 are connected using Media Transfer Protocol
(MTP) visible as virtual folder on Windows. (Those versions of Windows which support MTP.)
I suggest to use the synchronization tools of HTC and Samsung for those devices which mount itself as MTP device via USB instead of storage media device if such a software exists at all.
Some mobile devices can be configured to identify itself as storage media instead of MTP. But I don't know if HTC One M8 and Galaxy Note have such a configuration option for the USB interface.
You might contact IDM support by email regarding this issue as I'm not using mobile devices connected as MTP devices and therefore do not know at all how UltraCompare supports virtual folders.
Or has another user experience with synchronization between Windows computer and MTP mounted mobile device using UltraCompare Professional?
Update: I asked IDM support by email if Media Transfer Protocol and other virtual folders are supported by UltraCompare. And the answer was: no, not yet. Like I suggested, IDM support added this as feature request to their database for future versions of UC. Now it depends on how many users request this feature for UltraCompare. The more users request such a feature, the higher becomes the priority. But I think most users of mobile devices use the synchronization tool of the manufacturers of the devices. I think, this was the goal of the manufacturers for not mounting the flash storages anymore as storage devices. They don't want to give other applications access to the files on the mobile devices for various reasons.