Delete empty folders

Hello, 

I’m trying to delete some useless empty folders from my external hard drive (Mybook World White Edition wireless) but it keeps saying that it can’t be done because the folder is in use.

I even tried force deleting it using the line command “rm -r” in terminal but still couldn’t.

please help me! 

What’s the name of the folder that you are trying to delete?

Make sure that the folder is not being used by a backup application.

Also check if you have any hidden files on the folder that might be in use by some of the application on the computer.