On my old 24" iMac, (El Capitan) I've had this problem for a year where after copying a folder full of copied info from training CDs that I'd collected from various training books, at some point I threw something away (what exactly, I don't remember) and for some reason, the folder containing everything from the book: Illustrator 10 WOW! wouldn't delete from the trash, instead, I'd get a -50 error for every folder and disk that it was under. So when I empty my trash, I have to hit "continue" a lot. Dragging the stuff from the trash just copies it, and when I try to throw that away, I simply have more of the same problem. I've tried Trash It and Cocktail, Onyx and I've booted into safe mode and run the disk repair. Nothing works. I tried resetting the trash can using the Terminal. Nothing. So, a few days ago I bought a new Mac Mini, running El Capitan, and figured that I was free from this problem. But no. After copying the folder full of copied training CD info, like I had so long ago, the problem has returned somehow. My trash is full of this issue again, and I didn't even throw anything in the trash. I'm stuck with the exact same problem although I have a totally new computer and never threw anything in the trash again. Just copying the original folder full of folders of info copied from CDs caused the problem again. I tossed that folder into the trash, and erased that, but that didn't fix my problem. Any ideas? I'm at the end of my rope. With a new computer.