On either a Windows-based PC or a Mac, enter the disk management utilities, locate the flash drive and select the proper options to format the drive. Remember that formatting any drive erases any data that was already on that drive.
Formatting the flash drive is a handy solution when the drive returns error messages such as that the disk is full, even if there are no files on the drive.
Step 1: Verify the flash drive is inserted
Before attempting to format it, make sure the flash drive is firmly seated in the USB port of the computer. If the drive is not fully inserted, then the computer may not read the drive properly.
Step 2: Navigate to the flash drive
On a Mac, open "Disk Utility" and click the USB flash drive to select that drive. In Windows, click "Start" and then right-click "Computer." Click "Manage" to open "Computer Management." Click "Device Management," and then open the "Disk Drives" menu. Locate the flash drive, and right-click the drive's name.
Step 3: Choose the drive settings
On a Mac, click "Erase" and then choose "MS-DOS File System" from the "Volume Format" menu. Click the "Erase" button and then click "Erase" again. In Windows, click the "Policies" tab and then choose "Better Performance." Click "OK" and then click "Disk Management." Right-click the flash drive and choose "Format."
Step 4: Format the drive
On a Mac, erasing the drive should apply formatting. In Windows, type a name for the flash drive in the "Volume Label" box and choose the file system for the drive's new formatting. Select "Perform a Quick Format" and click "OK."