Mac drive glossary for Windows users
The words that come up when a Mac drive meets a Windows PC, each with a link to the guide that goes further. Quotes are from Apple and the drive makers, checked October 30, 2026.
- APFS (Apple File System)
- The default Mac file system "for Mac computers using macOS 10.13 or later" (Apple). Windows cannot read it without extra software. What is APFS
- HFS+ (Mac OS Extended)
- The Mac file system before APFS, "introduced with Mac OS 8.1" (Apple TN1150). Still common on older and "for Mac" drives. What is HFS+
- HFSX
- The case-sensitive variant of HFS+, "Mac OS Extended (Case-sensitive)" in Disk Utility.
- Journaled
- A file system that keeps a log of changes so it can recover after a crash or a pulled cable. "Mac OS Extended (Journaled)" is the usual HFS+ setting; LaCie notes that exFAT "is not a journaled file system".
- APFS container
- The partition that holds one or more APFS volumes sharing the same free space. Containers and volumes
- Volume
- What a Mac shows as a drive in Finder. One physical drive can hold several volumes. Diskferry lists each one with its format and size.
- Snapshot
- A saved, read-only state of an APFS volume. Time Machine on APFS disks keeps its backups as snapshots, which Diskferry does not read. Time Machine on Windows
- GUID Partition Map (GPT)
- The partition scheme Apple tells you to "Choose ... for all Intel-based and Apple silicon Mac computers". Windows understands GPT; it is the file systems inside it Windows cannot read.
- Apple Partition Map
- The scheme Apple says is "for compatibility with old PowerPC-based Mac computers". Not read by Diskferry in this version.
- EFI System Partition
- A small partition (200 MB in our test) that macOS adds when it erases a disk with GUID Partition Map. Windows shows it as a healthy FAT32 system partition. It holds none of your files. Disk Management
- exFAT
- The format both Mac and Windows read and write. Apple recommends it for "Windows volumes that are over 32 GB". Format a drive for both
- T2 chip
- Apple's security chip in Intel Macs from 2018 to 2020 (Apple lists the models). It encrypts the internal SSD; Diskferry does not support those SSDs.
- Fusion Drive
- A Mac storage option that "combines a hard drive and flash storage in a single volume" (Apple). Not supported by Diskferry. Fusion Drive on Windows
- FileVault
- macOS encryption for the Mac's startup disk. On Macs with a T2 or Apple silicon chip that disk is the internal SSD, which Diskferry does not support. Encrypted APFS
- .dmg (disk image)
- A whole volume in one file. Some are raw, many are compressed. Diskferry opens raw ones only. Disk image formats
- Sparse bundle
- A disk image stored as a folder of many files, "often used for Time Machine backups over a network" (Apple). Not supported by Diskferry.
- Time Machine
- The Mac's built-in backup. Its disks are not ordinary copies of your files and are not supported by Diskferry in this version.
- SHA-256
- A checksum: a fingerprint calculated from a file's contents. Diskferry calculates it for the original on the Mac drive and for the copy on your PC; if the two match, the copy is identical. Copying with verification
Last updated October 30, 2026. Still stuck? Support replies in person.
Related guides
- What is APFS? The Mac file system, explainedWhat APFS is, why Windows cannot read it, and what that means for your drive
- What is HFS+ (Mac OS Extended)?The Mac format before APFS, still on many external and backup drives
- What Disk Management shows for a Mac driveAn EFI System Partition and an unknown partition: what they are and what not to click
- Mac disk image formats on Windows: dmg, cdr, sparsebundleWhich Mac disk images Diskferry opens, which it does not, and how to convert one on a Mac
- Diskferry comparedMacDrive, Paragon, TransMac, HFSExplorer and the free options, with sources