3.0 Ultra USB 32 GB stops working while logging in

When I logged into a school computer, I plugged in my USB as the computer was loading.  From then on, the USB drive is shown, but it does not show any properties and cannot be clicked.  When I click on it, the computer tries to open it and just loads forever.  I tried using my home computer and the exact same thing happened.  The only solution I found was plugging it into a mac and then it magically worked.  I have to copy all files, then reformat on the mac.  

I was wondering why it does this and how can I fix the issue with a PC?  I’ve searched several forums and can’t find a similar problem.

Not aware of people plugging the drive in while Windows is loading.  Normal is to plug it in after Windows has booted or before Windows boots.

What format is the drive now?