The difference in Communication may lead to problems, because USB 2 is unidirectional (half-duplex), while USB 3 is bi-directional (full-duplex). The important differences are visuals (Because they are the only way of determining which is which) and Communication. The functional differences are speed, communication, power consumption, cable length, capacity, price and some more. For those who don't, here is the short explanation of the visual and functional differences: The visual difference is the color of the block, blue for USB 2, and black for USB 3. Since USB 2 and USB 3 are pretty similar looking, you might not notice the difference between the two. Now, this might sound weird, but a lot of problems are actually solvable by simply uninstalling the driver (of course after pulling it out), and reinstalling it again. I would definitely recommend trying this out, if there is a driver-error listed as reason for the malfunctioning.

Both are possible and, most importantly, secure ways of trying to fix your dongle, since there is nothing to lose.

Should your driver be outdated, you should update it, or, which did actually work for me, uninstall all drivers. Since I tried a lot of possible fixes while doing so, I gathered a lot of valuable Information on this dongle, and am going to present these in hopes of helping those of you who also have problems with this dongle. Now, I did have some issues with the above mentioned Bluetooth dongle lately, but have been able to fix them.

Asus ut usb bt400