Erase and Format a Drive in Disk Utility: APFS vs ExFAT

Q: Should I encrypt it?

Choose APFS (Encrypted) for a Mac-only drive holding sensitive data. Don't encrypt a drive you'll use on Windows — Windows can't read APFS encryption.

Published ✓ Verified ⏱️ 2 min read November 23, 2025 · by Ryan Bennett

You want to erase an external drive on your Mac and pick the right format — APFS for Mac, or ExFAT so Windows can read it too.

Why: The format decides which systems can use the drive. APFS is built for macOS and isn’t readable by Windows out of the box; ExFAT works on both Mac and Windows and handles large files and drives. Disk Utility lets you choose the format while erasing.

Fix 1: Choose the right format first

APFS — best for drives used only with macOS 10.13 or later (Time Machine, app data, Mac backups). Variants: APFS (Encrypted), APFS (Case-sensitive), APFS (Case-sensitive, Encrypted).
ExFAT — use for drives shared with Windows that are over 32 GB (almost all external drives today).
MS-DOS (FAT) — use for Windows-compatible drives that are 32 GB or less.

Fix 2: Erase and format the drive

Open Disk Utility (Applications > Utilities > Disk Utility, or search with Spotlight).
Choose View > Show All Devices so you can select the whole device, not just a volume.
In the sidebar, select the device (the top-level entry for the drive, not the indented volume under it).
Click Erase in the toolbar.
Enter a Name.
Click the Format pop-up and choose APFS or ExFAT (see Fix 1).
Click the Scheme pop-up and choose GUID Partition Map.
Click Erase, then click Done.

Erasing deletes everything on the drive — back up anything you need first.

Fix 3: Format specifically for Windows

If the drive must work on a PC too:

Follow Fix 2, but at the Format step choose ExFAT (over 32 GB) or MS-DOS (FAT) (32 GB or less).
Use GUID Partition Map for the scheme for general use; some older PCs expect Master Boot Record — choose that only if the PC won’t read the drive.
Keep the volume name short (MS-DOS FAT allows up to 11 characters).

FAQ

Can Windows read an APFS drive? Not without extra software. If you need both Mac and Windows to read and write the drive, use ExFAT.

Should I encrypt it? Choose APFS (Encrypted) for a Mac-only drive holding sensitive data. Don’t encrypt a drive you’ll use on Windows — Windows can’t read APFS encryption.

Sources: Apple Support — Erase and reformat a storage device in Disk Utility on Mac · Apple Support — File system formats available in Disk Utility on Mac · Apple Support — Format a disk for Windows computers in Disk Utility on Mac