Finder fixes and how-tos

Copying a big file to a FAT32 drive

Updated 2026-10-30 · 4 min read

Finder is refusing the copy because the drive is formatted as FAT32, which cannot store a single file of 4 GB or more. Check the format, then reformat, pick another format, or split the file.

Why Finder says the file is too large

Finder's message reads: "The item “Holiday.mov” can’t be copied because it is too large for the volume’s format." It means the drive's format can't hold a file that size, and in practice that format is FAT32, which Disk Utility lists as MS-DOS (FAT). FAT32 cannot hold one file of 4 GB or more (the exact ceiling is 4 GiB minus one byte). The drive can have 500 GB free and the copy still fails, because the limit is on a single file, not on free space.

Three ways round it:

1. Reformat the drive as exFAT, which works on Mac and Windows. This erases the drive.
2. Reformat as APFS or Mac OS Extended if only Macs will use it. This also erases it.
3. Split the file into pieces under 4 GB, if you can't erase the drive.

Check the format first, below, so you know it really is FAT32.

Check the drive's format

Plug the drive in, then run this in Terminal, replacing the name with your drive's:

diskutil info "/Volumes/<DriveName>" | grep -E "File System Personality|Name \(User Visible\)"

A FAT32 drive prints MS-DOS FAT32 and MS-DOS (FAT32). An exFAT drive prints ExFAT, and a Mac drive APFS or a Mac OS Extended name. You can also open Disk Utility, choose View > Show All Devices, select the drive's volume, and read the format on the right.

If the format is exFAT, APFS or Mac OS Extended, FAT32 is not your problem, and this fix does not apply. Check what the drive is plugged into and whether it is a network share, which can have its own limits.

Reformat as exFAT

This is usually the fix you want: exFAT has no 4 GB file limit, and both macOS and Windows read and write it. Many recent cameras and TVs read it too, but not all of them, so check the manual of any device that has to play from the drive.

Erasing deletes everything on the drive, so copy it all off first. Then:

1. Open Disk Utility (Applications > Utilities).
2. Choose View > Show All Devices, and select the drive itself (the top entry for it, not just the volume under it).
3. Click Erase in the toolbar.
4. Give it a name, set Format to ExFAT, and set Scheme to Master Boot Record, which Apple's guide recommends for compatibility with all Windows computers. GUID Partition Map suits Macs and, Apple says, some newer Windows PCs.
5. Click Erase.

Apple's guide for Windows-compatible drives suggests MS-DOS (FAT) only for disks of 32 GB or less and ExFAT above that. For a file over 4 GB, choose ExFAT whatever the drive's size. Our post on formatting a drive for Mac and Windows covers the options in more detail.

Reformat for Macs only

If the drive will only ever be plugged into Macs, APFS is the modern choice. Mac OS Extended (Journaled) is the older Mac format, for drives that must work with very old versions of macOS. Windows will not read either without extra software, and neither will most TVs. Erase it the same way as above and pick the format from the menu.

Split the file instead

When you can't erase the drive, because other people's files are on it or because a device needs FAT32, cut the file into pieces below the limit. Pick a size comfortably under 4 GB. In Terminal:

cd ~/Desktop
split -b 3g Holiday.mov Holiday.mov.part_

That writes Holiday.mov.part_aa, Holiday.mov.part_ab and so on, each at most 3 GB. Copy those to the drive. To rebuild the file on a Mac later, copy the parts into one folder, cd to it and run:

cat Holiday.mov.part_* > Holiday.mov

The shell expands part_* in alphabetical order, which is the order split wrote them in. For a folder, compress it first (select it in Finder and choose Compress from the File menu; the item carries the folder's name), then split the resulting .zip the same way and rejoin it with cat before opening it.

zip -s can also write a split archive, but the unzip that ships with macOS says in its manual that it doesn't support multi-part archives, and on the Mac used for this guide a split archive rejoined with zip -s 0 failed unzip's own test. Plain split and cat gave back an identical file. A TV or car stereo playing the file directly cannot join pieces, so for those you need the drive reformatted or the video re-encoded to a smaller file.

Devices that insist on FAT32

Some TVs, car stereos, older cameras and game consoles read only FAT32. They also cannot play a file of 4 GB or more from it. Check the device's manual for which formats it takes before erasing. Older models may reject exFAT, in which case a smaller or recompressed file is the only fix.

Seeing which files are over the limit

Before you start, it helps to know which files won't fit. In Everywhere, type size:>4gb and sort by Largest to list everything bigger than 4 GB, biggest first. Add a word such as path:Movies to keep it to one folder. It covers Movies, Desktop and other protected folders, and external drives, once you've given it Full Disk Access.

Common questions

Why does my Mac say the file is too large for the volume's format?

The drive is almost certainly FAT32 (shown as MS-DOS (FAT) in Disk Utility), which cannot store a single file of 4 GB or more. Free space does not matter, only the size of the one file.

How do I copy a file larger than 4 GB to a USB drive on a Mac?

Reformat the drive as exFAT in Disk Utility after copying its contents elsewhere, or split the file with split -b 3g and copy the pieces. Rejoin them with cat.

Does exFAT work on both Mac and Windows?

Yes, both can read and write exFAT, and it has no 4 GB limit on a file. Some older TVs and cameras only read FAT32, so check the device first.

Will reformatting a USB drive on a Mac erase my files?

Yes. Erasing in Disk Utility removes everything on the drive, so copy your files somewhere else first and copy them back afterwards.