Windows will not format any card larger than 32GB to Fat32- those will format only to EXFAT/ There are a number of freeware programs which will format the larger cards to fat32. Always format cards in-cam after this; with Mobius that us done with the msetup GUI.
If you want to read the card or do anything else with it, that is best done with the card out of the cam in a card reader.
Windows can get cranky with added 'drives' trying to run them in ways you might not want. My workaround is to go to where the drives are listed (My PC in w8), right click on the drive, then click 'open' which will let you choose how to deal with things instead of windows. Also in than menu will be options on what you want windows to do with these by default in the future
Phil