Genuino Uno works on Mac, not recognized on Windows

I have a Genuino Uno that I initially set up, and compile sketches with on my Mac. I have an Nano that I set up at school using Windows. The Mac won't recognize the Nano no matter what I do, and FTDI I install. Windows won't recognize the Genuino Uno when I try to do work with the Uno at school.

The Windows PC will see the Uno as a USB device but I cannot initialize it. My instructor was a bit baffled by the situation. Wondering if anyone else has run into, and then rectified a similar situation.

Cheers.

I suppose, you are using clones? Then go and look for "driver arduino clone" (use the search button of this forum or google the I-Net) and this should get you some steps further.

If you are on Sierra/Mac - there are reported problems even with original Arduinos, but some people got it to work, so search for it in the forum ("Sierra Arduino"