Mac OSX 10.10 Yosemite, Error Message: "The operation cannot be completed because an item with the name ".DS_Store" already exist"

I got this error message trying to do a basic thing: copy a folder from one drive to another.

Not sure how/why this bizarre error is showing up, in any case the workaround seem to be to simply copy again, at which point you're asked the usual: "A folder named ' ' already exists in this location, do you want to replace it with the one you are copying?", click "replace" and off you go.