winAPFS - the Apple filesystem, without the Mac.
Create, mount, read and write real APFS volumes on Windows. Encrypted, compressed, and structured exactly the way macOS expects - so one external SSD serves both machines, with nothing to reformat and no second drive to carry.
One drive, two computers
Cross-platform work runs on external SSDs, and that is exactly where Windows storage gives you the worst of the options. Windows cannot see an APFS drive at all, so the usual answer is to reformat it for Windows and give up everything APFS provides - or to carry two drives and copy between them.
- Windows cannot mount APFS - a drive written on a Mac simply isn't there when you plug it into a PC
- exFAT has no compression and no encryption - the format most people fall back to protects nothing if the drive is lost
- NTFS and exFAT slow down on portable SSDs - most of all across the thousands of small files a real project folder contains
- Reformatting for Windows costs you the Mac side - snapshots, native encryption, and APFS itself all go
What winAPFS does
💾 Create and use APFS volumes
Format, mount, read and write true APFS volumes from Windows. Not read-only access to a disk someone else made - volumes created from scratch on your PC.
🔒 macOS-native encryption
The same APFS volume encryption macOS uses. A Mac unlocks the drive with its password and mounts it natively, keys and structure intact.
📦 macOS-native compression
Transparent APFS compression that shrinks data on disk and stays fully decodable on macOS. No archive to unpack, no separate tool at the other end.
🧩 Both at once
Compressed and encrypted together, unified in the native APFS format - not two layers stacked on top of each other by two different products.
Performance where it matters
On external USB SSDs, winAPFS writes faster than the filesystems Windows ships with - in the operations that actually take up your day.
How it compares on an external USB SSD
| Capability | winAPFS | NTFS | exFAT |
|---|---|---|---|
| Big-file write speed | ~36 MB/s | ~26 MB/s | ~24 MB/s |
| Big-file write, compressed | ~32 MB/s | ~6 MB/s | Not supported |
| Small-file write speed | ~7 MB/s | ~0.3 MB/s | ~0.1 MB/s |
| Read speed | ~31 MB/s | ~40 MB/s | ~40 MB/s |
| APFS compatibility | Full | None | None |
| Compression | Yes, APFS-native | Yes, per-file and deferred | No |
| Encryption | Yes, APFS-native | Yes, BitLocker | No |
| Compression with encryption | Unified, native APFS | Stacked layers only | No |
| Readable on a Mac | Natively, as APFS | Read-only | Yes |
Measured on a 2 TB USB SSD under Windows 11, over a fixed 1 GB corpus: 59 large files for the big-file phase, 3,000 small ones for the small-file phase. Big-file write is an order-controlled mean, with each filesystem rotated through every position and the drive reset between runs. Your own numbers will depend on the drive, the port, and the PC.
Where winAPFS doesn't lead
The write advantage above is specific to slow external media, and it isn't free. Here is the other half of the same test run.
- Reads are slower than native - on the same USB SSD winAPFS reads at about 31 MB/s where NTFS and exFAT reach the drive's ~40 MB/s ceiling. That is roughly three quarters of what the hardware can do, and the gap is the cost of running as a userspace filesystem rather than a kernel driver
- It isn't faster code - take the slow drive out of the picture, writing instead to a cached virtual disk on an internal NVMe, and NTFS has around seven times more write headroom. winAPFS wins on USB by keeping a slow device continuously busy, not by being quicker in software
- Compression costs throughput - winAPFS compresses synchronously, as part of the commit, which cuts its ceiling from about 274 to 92 MB/s. NTFS compression looks cheaper only because it is deferred: it happens after the copy has already reported success
None of this shows up on an external SSD, which is what winAPFS is built for. On faster internal storage, the Windows filesystems win, and we would rather say so here than have you find out afterwards.
Who it's for
Working across both
Your Mac is where the work starts and a Windows PC is where it has to land, or the other way round. One drive should be enough for that.
Media and large data sets
Footage, image libraries, engineering and research output - the sets big enough that a slow external drive is measured in lost hours.
Drives that leave the building
An encrypted APFS volume that a Mac opens natively, so the drive being lost is an inconvenience rather than a disclosure.
Verified, not assumed
A filesystem is the one piece of software that cannot be roughly right. Everything winAPFS writes is checked against the real thing.
- Checked clean - every volume in the test matrix passes the standard APFS consistency check with no errors, in every mode: plain, compressed, encrypted, and both at once
- Byte-identical - a SHA-256 round-trip confirms that what was written on Windows comes back exactly as written, not merely close enough to open
- On real hardware - the headline figures come from a physical 2 TB USB SSD under Windows 11, not from a disk image or a simulated device
- Order-controlled - each filesystem was rotated through every position in the test order with the drive reset between runs, so nothing gains from going first. Variance across positions stayed under 1.5%
- Nothing leaves your PC - winAPFS is a filesystem, not a service. No account, no cloud, no subscription, and no telemetry going anywhere
Support
Need help with winAPFS? We're here to assist you.
Contact Us
winAPFS hasn't launched yet. For questions, feature requests, or to be told when it ships, please email us at:
winAPFS is an independent APFS implementation for Windows from IBC Partners. It is not affiliated with, authorized by, or endorsed by Apple Inc. APFS and macOS are trademarks of Apple Inc.