I just updated my MacOS to OS X El Capitan. So, I was about to print my files but the device connected to the printer was a Windows. But when my USB flash drive was connected to the computer, it asked for a formatting. It happened twice and I already formatted it twice too. Does it have anything to do with the new MacOS or was it just my USB flash drive? I always format it to MS-DOS (FAT32).
MacBook Pro, Mac OS X (10.7.5)
It is not clear what you are doing. Are you copying files from your Mac onto a usb device then connecting the device to a Windows computer for printing?
Are you sure it is formatted Fat32 or is your usb device formatted for the Mac? If so, Windows will not recognize the usb device formatting and will want to format it for Windows. If you format it for Windows on the Windows computer you will lose the files you loaded onto it from your Mac.
Sorry if I misunderstood your post.
Using a Mac to format a device (USB Flash drive for example) for Windows use doesn't always do as good a job as using a Windows computer for formatting. Try formatting the Flash drive on the device connected to the printer and since you always use FAT32, the Flash drive should work fine with both systems. BTW, new Flash drives generally come formatted so that they'll work with both OS's.
USB Flash Drive always asks for formatting on Windows
