I'm a photographer and I'm new to Mac. So, I KNOW when I first got my Mac, I had hooked up my USB external to the computer and moved some files onto the Mac. SO I have done it in the past. Today I finished a session and wanted to move the edited images from my computer to the external to back up. I do have enough room on the external . I am unable to drag the folder from my desktop to the external. I am also unable to move anything from the external TO the trash. I can move things from external to the desktop. But not to the Trash. And I can't get the folder dragged onto the external. Is it possible I've locked something? Any tips? Tricks? Check here's? Thanks for any help. I don't know what kind of external it is. Its just a box that holds my sessions and documents PS: I do have a small thumb drive and I was able to copy my folder to it. So, not sure why issues with the other thing. Perhaps not an issue with my Mac at all since I could do it with my thumb drive.