“Too large for the volume’s format” on Mac: how to copy files over 4 GB

By Ting Tze Chuen · Updated October 7, 2026

What does “too large for the volume’s format” mean?

When you drag a big file to a USB stick or SD card, Finder may stop with this message:

The item “holiday.mov” can’t be copied because it is too large for the volume’s format.

It isn't about free space. It means the drive's file system, the format it was set up with, has a maximum size for a single file, and your file is over it. Almost always that file system is FAT32, which macOS calls MS-DOS (FAT). Many USB sticks and smaller memory cards come formatted this way because nearly every device can read it.

FAT32 stores each file's size in a 32-bit field, so the largest possible file is 4,294,967,295 bytes. Microsoft lists FAT32's maximum file size as 4 GiB in its file system comparison. I checked the exact boundary on a FAT32 volume in macOS: a 4,294,967,295-byte file was written fine, and one more byte failed with “File too large.”

Finder counts a gigabyte as a billion bytes, so the limit shows up as roughly 4.29 GB in Get Info. A single 4K video clip, a disk image or a large archive can easily pass that.

How do I check what format my drive uses?

Any of these three ways works. Look for MS-DOS (FAT32) or MS-DOS (FAT).

• Finder: select the drive on the desktop or in the Finder sidebar, choose File > Get Info, and read the Format line.
• Disk Utility: open it from Applications > Utilities and select the volume in the sidebar. The format is shown under the volume's name.
• Terminal: run diskutil info with the drive's mount point and look for the file system lines.

diskutil info /Volumes/MYDRIVE | grep -i "file system"

On a FAT32 drive this prints File System Personality: MS-DOS FAT32. The full diskutil info output also shows the Part of Whole identifier (such as disk4), which you need if you reformat from Terminal.

Which format should I use instead?

Pick the format by where the drive needs to work. All of these handle files far larger than 4 GB except FAT32.

Apple's own guidance in File system formats available in Disk Utility is to use MS-DOS (FAT) for Windows volumes of 32 GB or less and ExFAT for larger ones, and APFS as the format for macOS 10.13 or later. For files over 4 GB, exFAT is the right Windows-compatible choice whatever the drive's size.

A note on NTFS: drives that come pre-formatted for Windows are often NTFS. macOS mounts them read-only, so you'll see a different problem (you can't copy anything onto them), and Disk Utility doesn't offer NTFS as a format. Writing to NTFS from a Mac needs a third-party driver.

How do I reformat a drive to exFAT in Disk Utility?

1. Open Disk Utility (Applications > Utilities).
2. Choose View > Show All Devices, so you can select the whole drive rather than just its volume.
3. In the sidebar, select the external drive (the top-level device, usually named after its maker). Check the size and name match the drive you mean to erase.
4. Click Erase.
5. Set Scheme to GUID Partition Map.
6. Set Format to ExFAT (or APFS for a Mac-only drive).
7. Type a name for the drive, then click Erase and, when it finishes, Done.

These steps follow Apple's Erase and reformat a storage device guide. When it's done, check the format again with Get Info before copying your files back.

How do I reformat from Terminal with diskutil?

The Terminal equivalent is diskutil eraseDisk. First, find the drive's identifier:

diskutil list external

Each external drive appears with an identifier like /dev/disk4 along with its size and partitions. Then erase the whole disk as exFAT with a GUID partition map:

diskutil eraseDisk ExFAT MYDRIVE GPT disk4

The arguments are the format (ExFAT, APFS or JHFS+ for Mac OS Extended, Journaled), the new name, the partition scheme, and the disk. Run diskutil listFilesystems to see every format name it accepts.

Can I copy a file over 4 GB without reformatting?

Yes, by splitting it into pieces under the limit. This is useful when the drive has to stay FAT32 or you're just moving a file to another Mac.

With split and cat. Both are built into macOS. Split the file into 4,000 MB pieces:

split -b 4000m holiday.mov holiday.mov.part-

That creates holiday.mov.part-aa, holiday.mov.part-ab and so on. Use 4000m rather than 4g: 4g means exactly 4 GiB, which is one byte over FAT32's limit. To rejoin on a Mac, copy the pieces to the same folder and run:

cat holiday.mov.part-* > holiday.mov

With a split zip archive. The built-in zip can write an archive in parts:

zip -s 4000m holiday.zip holiday.mov

This produces holiday.z01, holiday.z02 and a final holiday.zip. Keep all the parts together. To rebuild a single archive and then extract it on a Mac:

zip -s 0 holiday.zip --out holiday-whole.zip
unzip holiday-whole.zip

Video barely compresses, so zip won't save much space. Its main advantage is that the pieces travel as one recognisable archive. Whichever method you use, confirm the rebuilt file matches the original by running shasum -a 256 on both and comparing the hashes (more in how to verify a file copy on Mac).

Is exFAT safe for large video files?

It works, but it's less forgiving than APFS. exFAT has no journal (Microsoft's comparison table lists metadata journaling as NTFS-only), so unplugging the drive without ejecting it, or a flaky cable during a copy, can leave files damaged with no error message. The exFAT corruption guide covers the causes and how to avoid them.

Big files are where this hurts most: one bad block in a 40 GB clip can ruin the recording, and you may not notice until you scrub to that point. So after copying large files to an exFAT drive, verify them against the originals before you delete anything.

VerifiedCopy does that as part of the copy. It writes each file in chunks (4 MB by default), reads every chunk back from the drive and compares its SHA-256 hash with the source. If a chunk doesn't match, only that chunk is rewritten and checked again, so a single bad block in a huge video file doesn't mean starting the whole copy over. A full-file SHA-256 check follows by default. Note that VerifiedCopy can't get around FAT32's 4 GB limit; reformat the drive first.