Ciao @cedrone
è necessario utilizzare un programma : minitool partizion wizard per 64Gb
For information : if you are using a 64Go SDCard, your formater software may force format in exFAT.
So if you have this problem, you can try minitool partition wizard (windows only) http://www.partitionwizard.com/free-partition-manager.html
create as primary FAT32