This weekend I assisted in an Arduino workshop for kids. They all came with their own computers and we supplied LEDs, breadboards and cables. Overall it was great fun, but for some reason - a few of the kids were unable to get the Arduino tool up and running.
I reinstalled and upon reinstalling, I noticed there was something wonky about the driver installation. It turns out that with Windows 8.1, unsigned drivers are no longer allowed & as far as I can remember - the Arduino drivers have never been properly signed?
For our workshop, this meant that 3 of 14 kids had to share equipment with other kids. I’ve found workarounds ( http://www.makeuseof.com/tag/how-can-i-install-hardware-with-unsigned-drivers-in-windows-8/ ), but this is really something that the Arduino team should solve ASAP as it screws thing up for those of us that host workshops to teach microcontrollers.