Need to copy video from 1 thumb drive to another. Have the video already copied on iMac

Many thumb drives come pre-formatted with FAT32. FAT32 has a limit of 4 GB per file, and some implementations of FAT32 have an limit of 32 GB per volume.

My guess is that perhaps the "family video" thumb drive has individual files larger than 4 GB – and was formatted using exFAT, to be able to hold them. Your thumb drives, being 32 GB or under in size, probably are formatted as FAT32 drives. If you can copy the videos to your Mac's drive, but not to these 8 and 32 GB thumb drives, then I'd say that the chances of FAT32 being the problem are very high indeed.

One way around this might be to reformat the 8 and 32 GB thumb drives as exFAT drives, using Disk Utility.

If they reuse to accept a new format, note that exFAT is the standard filesystem on SDXC cards with a capacity of 64 GB or more. It might also be more common on new 64+ GB thumb drives than on new <= 32 GB ones.

BDAqua wrote:

Ah, good use of them, I was afraid you were using them for backups! :(

Don't you know by now that you should use Zip disks (<CLICK> <CLICK> <CLICK>) for backups? Or perhaps encourage your enemies to use Zip disks for backups, so when they go to retrieve their data, you can hear the sound of wailing and gnashing of teeth …

I also remember horror stories about the bad old days of 5.25" and 8" floppy disks – when the disks had soft-sided cases and were really "floppy". Horror stories about secretaries rolling them through IBM Selectrics, in order to neatly type on their labels … or pinning them to the sides of file cabinets with strong magnets.

Unlike the <CLICK> of Death, those were probably jokes and Urban Legends …

The ZIP® Disks ceased being a problem at all when I got rid of the Iomega drivers or whatever they were & used the Intech drivers! :)

But I have $800 worth of unopened Optical Discs, I think the hold over 80MB each!

How is the target drive formatted?

Depending on the format, there are file size limits depending on the format of the drive.

P.S. – Since these are "family-valuable" videos, I would recommend backing them up to hard drives somewhere – and not relying solely on the data retention capabilities of USB flash drives.

USB Flash drives the least reliable form of storage... & have no warnings before everything just disapopears.

Ah, good use of them, I was afraid you were using them for backups! :(