---
id: mac-storage-basics.why-cant-i-copy-a-file-larger-than-4gb-to-my-usb-drive
url: https://storagestudio.us/faq/mac-storage-basics/why-cant-i-copy-a-file-larger-than-4gb-to-my-usb-drive
category: "Mac storage basics"
subcategory: "Disks, APFS and formats"
question: "Why can't I copy a file larger than 4 GB to my USB drive?"
alt_questions:
  - "file too large for usb drive mac"
  - "fat32 4gb limit"
  - "can't copy large file to flash drive"
  - "ms-dos fat file size limit"
  - "usb stick won't take big file"
short_answer: "The drive is formatted MS-DOS (FAT32), which can't store files of 4 GB or more. Back it up and reformat as exFAT (Mac and Windows) or APFS (Mac only)."
tags: ["fat32", "usb", "formats"]
related: ["https://storagestudio.us/faq/mac-storage-basics/what-format-works-on-both-mac-and-windows", "https://storagestudio.us/faq/mac-storage-basics/how-do-i-erase-or-format-a-drive-on-a-mac"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# Why can't I copy a file larger than 4 GB to my USB drive?

The drive is almost certainly formatted as **MS-DOS (FAT32)**, which can't hold a single file of 4 GB or larger. Reformat it as **exFAT** (works with Mac and Windows) or **APFS** (Mac only) in Disk Utility — erasing deletes everything on it, so copy its contents off first.