Why your Mac cannot write to an NTFS drive

The drive is formatted NTFS. macOS mounts NTFS read only. Nothing is broken and nothing needs repairing. You can copy files off it all day. You cannot save, rename or delete anything on it until something else does the writing for you.

The important part comes next. There is data on that drive. Every route out of this has a wrong order that destroys it.

What the symptom looks like

The drive mounts. Finder shows it in the sidebar. Files open, copy to the Mac and preview normally.

Then anything that writes fails. Dragging a file on gives a crossed out circle. Rename does nothing. Delete is greyed out. Get Info reports read only under Sharing and Permissions. Unlocking the padlock changes nothing.

People read that as a permissions problem and start changing permissions. The permissions are fine. The format is the issue.

Why macOS does this

NTFS belongs to Microsoft. macOS ships a driver that reads it and does not ship one that writes it.

Every page you will find on this states the reason as licensing. That is worth treating carefully, because Apple has never published a reason at all. What is actually verifiable is narrower and still enough.

NTFS is proprietary and undocumented, so a write implementation has to be reverse engineered or licensed. A read implementation that misunderstands a structure shows you the wrong thing. A write implementation that misunderstands one corrupts the volume. The asymmetry between those two outcomes explains a conservative default without needing anybody's motive.

This is a design decision, not a fault. No macOS update will change it. No setting turns it on. Disk Utility will not repair it, because there is nothing to repair.

The Terminal trick this page will not give you

macOS does contain write code for NTFS. It is disabled. A few lines added to a system file switch it on.

Almost every result for this question publishes those lines. Read them closely and each one attaches a warning to its own instructions, describing the driver as experimental, unstable or capable of corrupting the drive.

Weigh that against the situation you are in. There is data on this drive that matters enough for you to be reading about it. The proposed fix is an unsupported code path, turned off by its own vendor, applied to the only copy.

Beyond the risk it also barely works. The volume stops appearing in Finder normally. The setting has to be redone per drive. An update can undo it. It proves the code exists. It does not give you a way to work.

Get the order right first

Whatever you decide, one sequence protects you and the reverse of it does not.

People get this backwards because the drive is the thing in front of them and the fix feels like it belongs to the drive. The data is the part that cannot be replaced.

The four ways out

The fourth is the one nobody suggests, because no product sells against it. If the drive came from a Windows PC that still exists, putting the files on over a network or a stick avoids the entire problem.

The third is a real option and this page has nothing against it. A driver from an established vendor is not a hack. It does install software that sits deep in the system, so it wants the same judgement you would apply to anything else operating at that level.

Why this catches people who never had the problem before

The question arrives in waves and the story behind it repeats.

A Windows machine gets replaced by a Mac. The drive that carried everything between them stops accepting files. Or a drive comes back from somebody else, formatted on their machine. Or a new drive is plugged into a PC first, which formats it NTFS without asking, then reaches the Mac later.

In every version the drive worked yesterday. Nothing about it has changed. What changed is which operating system is asking. That is worth knowing before you spend an evening on permissions and disk repair.

It also explains why the drive is so likely to hold the only copy. A drive that has been moving between two machines is a drive nobody has backed up, because it felt like the backup.

Reformatting is not a repair

Disk Utility offers Erase, the drive turns writable afterwards, so every guide mentions it. Two things get skipped.

It erases. Not the format, the contents. Everything on that drive goes. It is frequently the only copy of what it holds, since it came from a machine you no longer have.

It is one way. There is no conversion from NTFS to anything else that keeps the files. Erase, then copy back.

Which format to erase it to is a separate question. It turns on what else has to read the drive afterwards rather than on anything about NTFS. Work through it in the guide to picking a format for an external drive.

When it is not NTFS at all

Three other things produce a read only drive and none of them is a format problem.

The drive has a physical lock switch. SD cards and a few enclosures have one. It overrides everything.

Ignore ownership is unticked. Get Info on the drive, at the bottom of Sharing and Permissions. On a drive carrying account permissions from another machine, ticking it makes the drive writable again.

The volume was not unmounted cleanly. Windows fast startup leaves NTFS volumes in a state macOS refuses to write to even with a driver installed. Shutting the PC down properly rather than sleeping it clears that.

Check the format first. Get Info on the drive names it in one line. If that says NTFS, the rest of this page applies.

The short version

Read only is the format rather than a fault. Nothing on the Mac fixes it. Copy what matters off first and open the copies. Then choose between leaving the drive alone, reformatting it, buying a driver or writing from the Windows machine.

The one thing worth avoiding is the Terminal route, on the only copy of anything you care about.