One drive for a Mac and a Windows PC: which format to choose and how to set it up
ExFAT works on both, APFS is Mac only, NTFS is read only on a Mac. Which to pick for a shared drive, how to format it, and the one setting that matters.
You bought an external drive to move files off your Mac, and you also want to plug it into a Windows laptop at work. The format you pick decides whether both computers can write to it, and one wrong choice means the PC cannot see it at all.
The short answer
| Format | Mac | Windows | Best for |
|---|---|---|---|
| ExFAT | Read and write | Read and write | A drive shared between Mac and PC |
| APFS | Read and write | Not readable | Mac only, especially SSDs |
| Mac OS Extended (Journaled) | Read and write | Not readable | Time Machine on older Macs, hard disks |
| NTFS | Read only | Read and write | A Windows drive you only read from on a Mac |
| MS-DOS (FAT32) | Read and write | Read and write | Small sticks for TVs and cars, files under 4 GB |
For a shared drive, choose ExFAT. It has no 4 GB file size limit, which is what trips people up with FAT32, as covered in file too large for the volume format.
Formatting it on the Mac
- Copy off anything already on the drive. Formatting erases it.
- Open Disk Utility, choose View, Show All Devices, and select the drive at the top level.
- Click Erase. Name it, choose ExFAT, and choose GUID Partition Map as the scheme.
- Click Erase. The drive is ready in a few seconds.
GUID Partition Map works with every current Mac and every Windows PC from the last decade. Choose Master Boot Record only if a very old PC or a device like a TV refuses the drive.
The trade-off with ExFAT
- ExFAT has no journal, so pulling the cable out without ejecting can damage the file system more easily than with APFS. Always eject first.
- It does not support Time Machine. Keep backups on a separate APFS drive, or a separate partition.
- It is slower than APFS for lots of small files, which rarely matters for videos and photos.
Splitting one drive into two
A large drive can hold both: an APFS partition for Time Machine and an ExFAT partition for sharing. In Disk Utility, select the drive, click Partition, and add a second partition with its own format. Using part of a Time Machine drive for files walks through it.
# Check what format each connected drive uses
diskutil list externalRelated: MediaKit reports not enough space on device and Erase process has failed on Mac.
Common questions
What is the best format for an external drive used on Mac and Windows?
ExFAT. Both systems can read and write it and it has no 4 GB file limit. The one caution is to always eject it before unplugging.
Can Windows read an APFS drive?
Not without extra software. If a drive needs to work on a Windows PC as well, format it as ExFAT.
Should I choose GUID Partition Map or Master Boot Record?
GUID Partition Map for almost everything. Master Boot Record only for very old PCs or devices that refuse a GUID drive.