Your Windows drive opens on the Mac but will not let you copy anything to it
A Mac reads NTFS drives but cannot write to them. Why, what your options are, and the safest way to get files onto a drive that came from a Windows PC.
You plug in a drive from a Windows PC. Your files show up, you can open them, but you cannot drag anything onto it, and Get Info says You can only read. The drive is fine. It is formatted as NTFS, the Windows format, and macOS only reads it.
diskutil info /Volumes/YourDrive | grep -i "file system personality"If that says NTFS, you have three choices.
1. Reformat the drive as ExFAT (best if you can)
ExFAT is read and write on both Mac and Windows. Copy everything off the drive to one computer first, then erase it as ExFAT in Disk Utility and copy the files back. Formatting a drive for Mac and Windows has the steps.
2. Copy files from the Windows side
If the drive must stay NTFS, for example because it is a Windows backup, write to it from the PC and only read from it on the Mac. That is what the Mac is built to do safely.
3. Use an NTFS driver
Paid drivers add full NTFS writing to macOS. They are the right choice if you move between a Windows drive and a Mac every day. Free, unsupported methods that turn on the Mac's own experimental NTFS writing exist online, but they have a reputation for damaging files, so they are not worth the risk for anything you care about.
| Option | Cost | Risk | Best when |
|---|---|---|---|
| Reformat as ExFAT | Free | None, once files are copied off | You control the drive |
| Write from Windows only | Free | None | The drive is a Windows backup |
| Paid NTFS driver | Paid | Low | Daily use of NTFS drives |
| Experimental built-in write | Free | High | Never for important files |
If the drive also shows the wrong capacity, see USB drive showing the wrong size.
Related: disenter error and Mac drive can't be modified.
Common questions
Why is my external drive read only on Mac?
Most often because it is formatted as NTFS, the Windows format. macOS can read NTFS but not write to it. Reformatting as ExFAT gives read and write on both Mac and Windows.
Can a Mac write to an NTFS drive?
Not by default. A paid NTFS driver adds it safely. Free experimental methods exist but can damage files.
Will reformatting to ExFAT delete my files?
Yes. Copy everything off first, erase the drive as ExFAT in Disk Utility, then copy the files back.