How to format a USB drive or memory card: FAT32, exFAT or NTFS?

A brand-new USB drive stays invisible on some devices, an older memory card throws a "card error" in a camera, and sometimes a 5 GB file refuses to copy with a "too large for the destination" message. Most of the time nothing is broken: the drive is simply formatted with the wrong file system.

This guide walks through formatting a USB drive or memory card on Windows 11, macOS and Android, how to decide between FAT32, exFAT and NTFS, and what to do when the format will not go through. Every step is verified against current official documentation from Microsoft, Apple, Google and the SD Association.

One thing first: formatting is not a cleanup, it is a deletion. Read step one before you start.

1. Copy everything off the drive first Formatting removes the files for good. Apple's Disk Utility documentation states it plainly: erasing a storage device deletes everything on it, and if you have files you want to save, copy them to another storage device before erasing. Google's Android support page says the same for memory cards: if you format your SD card, data will be permanently deleted, so back up your files first. Plug the drive in, copy its contents into a folder, then open the copy and confirm the files really work. For photos and videos you cannot recreate, one copy is not enough; put a second copy somewhere else.
2. Decide between FAT32, exFAT and NTFS The deciding factor is not the drive but where you will plug it in. For a television, a car stereo, an older camera or a console that only reads simple file systems, go with FAT32; the SD Association lists FAT12/16 for cards up to 2 GB and FAT32 for SDHC cards from 2 GB to 32 GB. If you need to carry single files larger than 4 GB, or use the drive on both Windows and Mac, go with exFAT; Microsoft documents that FAT32 has a maximum file size of 4 GB, and Apple instructs you to choose ExFAT if the size of the disk is over 32 GB. The SD Association likewise specifies exFAT for SDXC and SDUC cards above 32 GB. Choose NTFS only if the drive will live on Windows machines and is a large external disk; Apple states outright that Disk Utility does not support NTFS format, which your Mac might be able to read from but not write to.
3. Format from File Explorer on Windows Plug the drive in, open File Explorer and find it under This PC. Right-click the drive and choose Format. In the dialog, pick your choice from the File system list (NTFS, exFAT, FAT32); Microsoft's format reference lists the valid file systems as FAT, FAT32, NTFS, exFAT, ReFS and UDF. Leave Allocation unit size alone on its default value, which Microsoft recommends for general use. Type a short name in Volume label so you can recognise the drive later, then click Start and confirm the warning.
4. Use Disk Management if the drive does not show up If the drive never appears in File Explorer or has no drive letter, switch to Disk Management. According to Microsoft's support page you can right-click the Start button and select Disk Management, select Search and type Disk Management then choose Create and format hard disk partitions, press Windows + R and type diskmgmt.msc, or open Computer Management and select Storage > Disk Management. Identify the drive by its size, make sure you are on the right row, right-click the volume and select Format, then accept the default settings with OK and confirm. Picking the wrong disk here wipes your computer's own drive, so check the size twice.
5. Know the difference between quick and full format The Quick Format checkbox turns a job of minutes into one of seconds, but it does not really clear the drive. Microsoft's support page puts it this way: the Perform a quick format option will create a new file table but will not fully overwrite or erase the volume. The command-line reference adds that /Q deletes the file table and the root directory but does not perform a sector-by-sector scan for bad areas, and that you should use it only on previously formatted volumes you know are in good condition. So if the drive has started throwing errors, or you are passing it on to someone else, leave the box unchecked for a full format; for routine housekeeping, quick is fine.
6. Prepare a drive over 32 GB for a device that demands FAT32 If a TV or stereo insists on FAT32 but your drive is 64 GB or 128 GB, FAT32 will not appear in the Windows dialog. Microsoft documents why: FAT32 has a maximum partition size of 32 GB, and you can still use a 64 GB or 128 GB USB key, but you have to format it to use only 32 GB of its space. To do that, right-click Start, open Terminal (Admin) and type diskpart; run list disk to see the disks, select disk X to pick your drive (confirm X by its size), clean to remove the existing partitioning, create partition primary size=32000 to make a 32 GB partition, then format fs=fat32 quick label="PORTABLE", assign to give it a letter, and exit. Microsoft notes that clean removes any and all partition or volume formatting from the disk with focus, so selecting the wrong disk empties that disk completely.
7. Erase and reformat with Disk Utility on a Mac Plug the drive in and double-click Disk Utility in the Applications > Utilities folder. Apple's documented sequence is: choose View > Show All Devices, select the device you want to erase in the sidebar, and click the Erase button. In the dialog, click the Scheme pop-up menu and choose a partition scheme, click the Format pop-up menu and choose your file system, type a name for the device, then click Erase and click Done. For a drive shared with Windows machines Apple's rule is explicit: choose MS-DOS (FAT) if the size of the disk is 32 GB or less, and ExFAT if it is over 32 GB. If a Security Options button is available you can raise the number of overwrite passes; Apple notes secure erase options are unavailable for SSDs and suggests enabling FileVault encryption instead.
8. Format a memory card on an Android phone You can either tap the notification that appears when you insert the card or go through Settings afterwards. Per Google's Android support page, for a new card swipe down from the top of the screen, tap the "SD card detected" notification, then select Format for portable storage or Format another way for internal storage. To switch an already-inserted card to portable storage, go to Settings > Storage > SD card, then Menu > Format > Format card. With portable storage you can save files like photos and videos, you cannot install apps on it, and you can move the card between devices. The phone prepares the card the way it wants it; if the card will also go into a camera, formatting it in that device or on a computer is the safer route.
9. If you get "cannot format" or "write protected" Check the physical lock first: full-size SD cards have a write protect switch on the edge, and the SD Association's documentation says it should be in the NOT PROTECTED (upward) position before formatting; for microSD cards the switch may be on the adapter instead. If there is no switch, or it is already open, look for a software lock on Windows: open Terminal (Admin), type diskpart, run list disk, select disk X for your drive, then attributes disk to read its state, and clear any lock with attributes disk clear readonly. Microsoft documents that attributes disk displays, sets or clears the attributes of a disk and that a disk must be selected with select disk for the command to succeed. If another program still holds the drive, a restart or the /X option on the format command forces the volume to dismount. If none of this helps, the drive may simply have reached the end of its life; do not keep anything on it as your only copy.

⚠ This guide is general information. Yudum cannot be held responsible for the outcome of following it; for official procedures always rely on the institution's own statement. Steps and fees change over time.

🎯 Related content

How to Record Your Screen on Windows, Mac, iPhone and Android You do not need extra software to capture what happens on your screen. Built-in recorders, their shortcuts and audio settings on four operating… How to create a Windows 11 installation USB drive Build a Windows 11 installation USB with the Media Creation Tool or the official ISO: how many GB the drive needs, what the system requirements are… How to free up space when your Gmail storage is full What to do when the "storage full" warning stops your mail: emptying the trash folders, search operators that find oversized attachments, and… Windows 10 support has ended: can your PC run Windows 11? Windows 10 reached end of support on 14 October 2025. Check whether your PC can run Windows 11 by testing TPM 2.0, Secure Boot and the official… How to free up space when the C: drive is full on Windows When the C: drive turns red, Windows slows down, updates fail and files won't save. Here is how to clear it step by step using Windows 11's Storage… How to measure your internet speed properly, and what to do if you are not getting the speed you pay for Saying "my internet is slow" proves nothing. For a measurement to carry any weight it has to be taken over a cable, with one device, and repeated at…