A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
I've noticed that if the file is open somewhere, it will give you this error. Try closing all instances of the file, then move it.
It also happens when the file is closed everywhere as several people have reported and as Msft themselves have confirmed by saying it's "by design". Clearly it's a bad design but not untypical of a co that's not known for its care for customers.