You can copy files to a USB flash drive in Windows 10 with File Explorer. Before disconnecting the drive, make sure the copy has finished and eject it properly so pending writes are not interrupted.
Copy files to the flash drive
- Connect the USB flash drive to the computer.
- Open File Explorer and select This PC.
- Open the USB drive and confirm that it has enough free space.
- In another File Explorer window, locate the files or folders you want to transfer.
- Select them, choose Copy, then paste them into the desired folder on the USB drive. You can also drag files between the windows.
- Wait for the transfer progress to finish.
Copying leaves the original files on the computer. If your goal is to move them, verify the copies on the flash drive before deleting the originals.
If a large file will not copy
A FAT32-formatted drive cannot store an individual file larger than 4 GB. If the drive must hold larger files, exFAT is often a practical removable-drive format for modern systems. Reformatting erases the drive, so back up its contents first.
Remove the drive safely
Use the Windows eject control or right-click the USB drive in File Explorer and choose Eject when available. Wait until Windows indicates that removal is safe before unplugging it.
If the drive disconnects during transfers, reports file-system errors, or becomes unexpectedly read-only, stop relying on it for important data. A flash drive is convenient transport storage, but important files should also exist in a separate backup.
Use Eject Before Removing the Flash Drive
After the copy finishes, use the USB drive’s Eject command from File Explorer or the taskbar when available, then wait for Windows to indicate that it is safe to remove the device. This reduces the risk of interrupting writes that have not finished.
FAT32 Has a 4 GB Single-File Limit
If Windows says a large file is too big for the destination even though the flash drive has enough free space, the drive may use FAT32. FAT32 cannot store an individual file larger than 4 GB. Reformatting to exFAT or NTFS can solve that limitation, but formatting erases the drive, so back up its contents first and choose a file system compatible with the devices that must read it.
Windows 10 Support Status
Standard Windows 10 support ended on October 14, 2025. Eligible Windows 10 version 22H2 consumer PCs can receive Extended Security Updates through October 12, 2027.
Matt Jacobs has been working as an IT consultant for small businesses since receiving his Master’s degree in 2003. While he still does some consulting work, his primary focus now is on creating technology support content for SupportYourTech.com.
His work can be found on many websites and focuses on topics such as Microsoft Office, Apple devices, Android devices, Photoshop, and more.