Hi maralynn7,
I think the reason why you're running into this issue is because your flash drive is probably formatted as MS-DOS FAT (FAT32). This format is commonly used on flash drives since both Windows and Mac computers can read and write to it. However, this format doesn't permit you to store files larger than 4 GB on the flash drive.
To fix this, you'll need to reformat (erase) your flash drive in Disk Utility. To do so:
- Open Disk Utility, which is in the Utilities folder inside the Applications folder.
- Select your external flash drive and click Erase. Choose a format based on the following:
- APFS and its variants: Recommended for solid state drives (SSDs), and only supported on macOS High Sierra or later. Supports full drive encryption and can be used as a boot drive. Not recommended for traditional hard drives or flash drives. Windows cannot natively read or write to this format.
- Mac OS Extended (Journaled) and its variants: Recommended for any drive that you wish to use exclusively with Macs. Supported by many versions of macOS and/or OS X, allows full drive encryption and can be used as a boot drive. Windows cannot natively read or write to this format.
- ExFAT: Recommended for drives that you wish to use with any computer. Supports files that are larger than 6 GB. Doesn't support full drive encryption and can't be used as a boot drive.
- MS-DOS FAT (FAT32): This is what your flash drive is currently formatted as.
Once you've formatted and erased your flash drive (as anything other than MS-DOS FAT) you should be able to copy the video onto your flash drive.
Hope this helps!