Not enough disk space to copy file

Hi,

I'm trying to copy a 1GB video onto a USB drive from my MacBook but it says I can't cause there's not enough disk space to copy it, which is baffling considering there are still 161GB free on the 256GB disk, so more than half and plenty to copy a 1GB file. I'd like to get an actual answer why this is happening when I have so much free space, instead of just recommendations on how to free up more space, it seems to me like this is an actual technical issue. I've also already emptied the trash, which had some 14GB in it + I erased a whole season of a show I was watching, which was a few GB as well, and I STILL can't copy the 1GB file even after restarting my MacBook, which doesn't even make sense mathematically speaking.

I expect better from Apple, this is just absurd honestly. Hope some of you can help with this.