I'm on a 2014 MacBook Air, 10.14.5
A couple of weeks ago I did a quick sweep of my files and drives to get rid of junk, mostly old photos and videos I had accumulated that I didn't need/want anymore. Everything deleted fine, except for one .mp4 file. This file, it seems, managed to get into my Bin, but is now stuck. I would really like to get rid of it - it was copied off an old USB drive and is about 5GB, which is a lot when you only have 10GB free space.
When I drag it anywhere, it just copies. When the bin is emptied, I get the message "....mp4 can’t be modified or deleted because it’s required by macOS".
I've looked for possible solutions, including turning off System Integrity Protection and reinstalling the OS but to no avail.
Please help! Sorry if I've missed any details