A colleague hands you an external hard drive containing massive project videos and documents created on a Windows workstation. You plug it into your Mac's USB-C port, open Finder, and all the directories appear seamlessly. You can double-click documents and stream video files without any hiccups.
The trouble begins the moment you attempt to drag a file from your Mac onto the external drive. A prohibited icon (π«) appears alongside your cursor. If you right-click the canvas, "New Folder" is greyed out, and pressing the Delete key does not even offer to move files to the Trash.
Your external drive is not broken, and your Mac's ports are working fine. You have run headfirst into a licensing barrier between Microsoft's proprietary NTFS file system and Apple's macOS. Here is how to write to an NTFS drive for free when you cannot afford to format it, and how to format it properly for painless cross-platform compatibility.
Why macOS Restricts NTFS to Read-Only
If you right-click the drive icon in Finder and select Get Info (Cmd + I), looking at the bottom Sharing & Permissions panel will reveal the status: "You can only read."
NTFS (New Technology File System) is Microsoft's proprietary storage format. Because of licensing restrictions, Apple builds native support to read NTFS volumes into macOS, but intentionally disables write and modification capabilities out of the box.
Commercial third-party file system drivers (such as Paragon NTFS or Tuxera) solve this with dedicated kernel extensions. While worthwhile for enterprise environments juggling dozens of NTFS drives daily, paying a $30 to $50 license fee is impractical for ordinary users who just need to copy a few presentations or files once in a blue moon.
The Free Workaround: Using Mounty for Mac
When an external drive already contains hundreds of gigabytes of vital data that cannot be offloaded elsewhere for formatting, the lightweight open-source tool Mounty for Mac is the most practical solution.
Mounty functions as a minimalist menu bar utility that safely invokes Apple's internal, experimental read-write kernel module to remount NTFS volumes in read-write mode. If you have Homebrew installed, you can set it up in Terminal with a single command:
brew install --cask mounty
Alternatively, download the official installer directly from mounty.app. Once launched, a subtle mountain icon resides in your menu bar. When you connect an NTFS drive, Mounty prompts: "Would you like to remount as read-write?" Approving this unlocks write capabilities immediately in Finder.
Crucial Rule: Never unplug the cable directly after writing via Mounty. Always click the Mounty menu bar icon and select Unmount first to allow pending write buffers to flush completely, preventing filesystem corruption.
Why You Must Avoid the Terminal fstab Hack
Older tutorials often advise modifying /etc/fstab in Terminal to force macOS into writing to NTFS natively without third-party software. Do not use this method.
Apple keeps this functionality hidden because its write routines are not production-stable against unexpected disconnects. An interrupted file transfer under a forced fstab mount can corrupt the NTFS Master File Table (MFT), leaving the volume unreadable on both macOS and Windows PCs.
The Permanent Solution: Formatting to exFAT
If you have temporary space to back up your drive's contents elsewhere, converting the drive permanently to exFAT eliminates operating system barriers forever.
Open Disk Utility (Applications βΈ Utilities βΈ Disk Utility). Select your external drive in the sidebar, and click Erase in the top toolbar:
- Name: Choose an alphanumeric name without special characters.
- Format: Select exFAT. (Avoid MS-DOS/FAT32, which refuses files larger than 4GB).
- Scheme: Choose GUID Partition Map.
Pro Tip: If you ever format an exFAT drive from a Windows PC, beware of the "Allocation Unit Size" setting. Leaving it on Windows defaults (often 128KB or larger) causes macOS to lag for minutes trying to mount the volume. Manually pick 16KB or 32KB cluster sizes on Windows for instant, frictionless mounting on both operating systems.
Use Mounty for immediate emergency file transfers, and transition to a well-configured exFAT format when time permits for seamless cross-platform productivity.