Format GPT hard disk in Windows to MBR & exFAT If you need to use big, over 2 GB files both in Windows and Mac OS X’s, MBR partition format and exFAT file system could be the most practical option for your mobile HDD. However, note that there have been reliability problems with exFAT in heavy use. Always keep a backup on a trusted media and FS. Mac OS X’s Disk Utility is easy to use, but what to do if you have to quickly reformat an GPT/EFI disk to MBR partition layaout and exFAT file system on Windows XP, 7, 10, 11...? Let’s assume the external hard disk is Disk 3 (check with Computer → Manage → Storage → Disk Management or command diskpart list disk, and list volume, etc) and that the drive letter is G. In Windows, choose Start → All Programs → Accessories → Command Prompt → Right-click & choose “Run as administrator” In ancient Windows XP, use Windows-R and cmd — for exFat support you have to install a patch first: http://support.microsoft.com/?kbid=955704 Type commands diskpart select Disk 3 clean create partition primary assign letter=g exit format g: /fs:exfat /q exit Some technical info: https://en.wikipedia.org/wiki/GUID_Partition_Table Note you can also delete, merge and extend partitions too with https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/diskpart - - - If you have to use Apple OS X (macOS) Disk Utility by command line, use diskutil list to locate the number of the disk to be formatted and e.g. diskutil partitiondisk disk3 1 mbr exfat my-500GB 100% to partition and format your 4th disk to be Windows compatible… the numbering starts from 0. </plaintext></body></html>