I have been using a SanDisk 32GB drive to transfer data between Windows and Macs.
All was going well until I renamed the drive before ejecting it from the Mac. It was then not visible on Windows and not visible when I went back to the Mac.
Some time pen drive showing in device manger but not in my computer , in other system its showing , so might be possible no drive letter assign for drive > go to control panel > Computer management > disk management > select storage or drive which is not showing > assign letter select any latter after doing above pen drive showing in my computer.