MacBook won't copy to a USB or external drive?
Read the message, apply the fix
When a Mac won't copy files to a USB stick or external drive, it's usually one of these: the disk is NTFS (a Mac can read it but not write), FAT32 can't hold files over 4 GB, there's a space or file-name problem, or the connection is unstable. Check the disk's format first, then use the table below.
MacBook Air / ProiMacMac miniUSB flash drives & external drivesLast updated
Which one are you seeing?
Select the disk in Finder and press ⌘I to check "Format"—that alone reveals the cause of most problems.
| Why | Solution | |
|---|---|---|
| Dragging in does nothing; can't delete or rename | The disk is NTFS, which a Mac can only read | Install CrossDriver NTFS to enable writing, or back up and reformat as exFAT |
| "File too large" or can't copy | The disk is FAT32 (Get Info shows MS-DOS (FAT32)), which limits single files to 4 GB | Back up, then reformat as exFAT or NTFS |
| "Not enough space," even after deleting files | Files deleted from an external disk go to that disk's Trash first | Empty the Trash, then copy again |
| Some files won't copy | The file name contains characters Windows doesn't allow, such as : * ? " < > |, or the path is too long | Shorten the file name and remove special characters, then copy again |
| Copy fails partway or the disk disconnects | Insufficient power, a loose cable or dock connection, or possibly a failing drive | Connect directly to the Mac and try another cable and port; if the drive makes odd noises, back up first |
NTFS drives: enable writing on your Mac
- 1
Download & install
Download CrossDriver NTFS and drag it into the Applications folder—no restart needed.
- 2
Plug in your disk
The disk appears in the app's sidebar, and the free version lets you browse it read-only and copy files to your Mac.
- 3
Turn on writing
Start a 7-day free Pro trial or upgrade to Pro to copy files straight onto the disk.
- 4
Eject before unplugging
When you're done, click "Eject" and wait for changes to be written to the disk before unplugging.
Q&A
Why can't my Mac copy files to a USB stick?
Most often the stick is formatted as Windows' NTFS, which macOS can read but not write. Next come FAT32, which can't hold a single file over 4 GB, a write-protect switch that's on, or a full disk. Select the stick in Finder, press ⌘I to check Format, then use the table in this guide.
What are all those files starting with ._ that I see on Windows?
When macOS writes to disks that don't support extended attributes, such as FAT32 and exFAT, it creates extra ._ files to store that information. You can delete them on Windows. By default, CrossDriver NTFS cleans up these Mac-generated metadata files when you eject.
Copying from a Mac to a USB or external drive is slow?
First make sure it's connected to a USB 3 or Thunderbolt port (USB 2.0 tops out at about 40 MB/s). Hard drives themselves typically manage 100–200 MB/s, and lots of small files copy more slowly than large ones. See Performance for speed comparisons.
Format as exFAT or NTFS?
Choose exFAT if you use both systems and mainly move files around; choose NTFS for high-capacity drives used mostly with Windows. See exFAT vs. NTFS: which to choose for the differences.
Does CrossDriver work on a MacBook Air with an M-series chip?
Yes. It supports MacBook Air, MacBook Pro, iMac, Mac mini, Mac Studio, and Mac Pro, runs natively on both Apple silicon and Intel, and works on macOS 12 Monterey, 13 Ventura, 14 Sonoma, 15 Sequoia, 26 Tahoe, and later.
Related products and guides
CrossDriver NTFS
Read and write NTFS external drives and USB flash drives on Mac.
Mac external drive is read-only
Five reasons an external drive shows as read-only or "You can only read."
exFAT vs. NTFS: which to choose
Sharing a drive between Mac and Windows: which format to choose.
Format an external drive as exFAT or NTFS on Mac
Format an external drive as exFAT or NTFS on a Mac.
Plug in a USB or external drive and try it free
Download CrossDriver NTFS and open your NTFS disk in Finder for free.
Download for Mac — Free preview