I work on an imac with OSX 10.9.5. Part of my work involves saving files recorded from several cameras and drones (I work in video editing). A couple of times has happened that I copy some files and then later when I go look for them, they're gone, we've lost some very important video footage that way. Today I was copying some footage we made yesterday, while at the same time doing some other stuff, I went to delete the trash bin... and it tells me that it can't empty it because the file XXX (one of the files I'm copying) is in use.... sure enough, when I check the folder I was copying, it deleted all the files except for that one. The files were never in the trash bin, actually all I did was to plug in the USB memory card in the reader and copy all the files to an external USB drive. Seems that the trash bin is getting confused somehow, and when I empty it it's deleting stuff from other folders and not what's actually in the trash. I copied the files again, emptied the trash bin, and it deleted them again, while what was actually inside the trash bin was still there. Any clues?... this scares me now because there's no telling what other footage files it might have deleted while emptying the trash bin like that.