You’d need to download a 3rd party formating program.
They’re generally all free, just like the fat32 format.
(Some formats / protocols are around , that companies have to pay Microsoft or whoever to utilise… which is why fat32 is great, and possibly why Windows doesn’t offer it 
I don’t think that is correct. I just formatted a drive to Fat32 using a Win10 system a couple of days ago. No issues using the stick on Mac or PC.
I think it was one of the previous windows versions which stopped offering fat32 as a formatting option.
If it’s back on windows 10, that’s great
Ex Fat is fine too 
It’s the more advanced replacement of Fat 32
I posted a tool that will make FAT32 drives out of any size drives so see my post (It says download tool here) that will give you all what you need to make any drive a proper MSDOS FAT32 drive properly converted with no issues.
I tried extFAT the my MCX8000 and it doesn’t recognize the the file format. Windows10 won’t format a larger USB stick 64GB or 128GB in FAT32 even when using DISKPART from the command line this is because windows doesn’t support volumes formatted in FAT32 larger than 32GB. I haven’t tried a 32GB flash drive yet but it should work just fine according to Microsoft. I find “free” tools from random websites to be generally dubious because freeware/shareware is notorious for sneaking nefarious applications onto your PC.
I apologize for the extra post. Just in case there are windows users who want to use the DISKPART utility to format their flash drives or external HDDs I put together a quick walk through.
DISKPART.pdf (196.0 KB)
exFAT NOT work with MCX8000…
Try to format 64GB usb drive to FAT32…
I have two 1TB drives formatted to Fat32 that I use for hopping files back and forth between Macs and PCs. Fat32 supports up to 2 or 3TB volumes I believe.
Formatted with the Windows 10 Format Tool?
Windows cannot format a disk larger than 32GB in FAT32. you could make an initial partition of 32gb on a magnetic drive and then make additional 32GB volumes and windows will pretend to see it as one drive. this method will not work with a removable flash drives. I’m not a Mac user so I cannot speak to Apple’s ability to preform the task being discussed. JonnyLove posted a tool in another thread that will format your flash drive in FAT32 beyond the 32GB limit in windows. I believe he said it Fat32Format you can find it here FAT32Format it’s freeware/shareware but it looks like our only option as windows users unless Denon can build in support for extFAT of NTFS.
For Mac Users I suggest SD Card Formatter 4.0 for correct FAT32 format. This is official software of SD Association: https://www.sdcard.org/downloads/formatter_4/
Is there anyone how use a Lexar S45 memorystick for the MXC8000. 128 GB.
Here is a link for windows users to Verbatim’s SmartDisk FAT32 Format Utility. this will format disks larger that 32Gb into FAT32 for use with your MCX8000. I successfully used to to format a 64GB flash Drive on a windows ten box.
I myself have formated a 128 GB Thumb drive and the MCX8000 would not recognise it at all. I tried Every format that I knew of and still nothing… I would suggest not formatting rather deleting all folders all day start over…