When using an A-series or Revolution system, the USB device must be formatted as FAT32.
You can format FAT32 using the following program: https://www.partitionwizard.com/download/pw10-free.exe. To convert an existing NTFS and keep your data you will have to pay for the upgrade. However, if the drive is free or you can afford to discard the data then right click on the partition and Remove it. Then do it again and format as FAT32. Finally, click on Apply. It will only take a few moments.