Q: I cannot empty trash on my Mac Pro when I have external drives attached

I have the same issue. It looks like no one has offered a solution. Correct?

Every file and folder in Mac OS X has some permission settings to help define what you or other users can do with the file or folder, for example whether you may modify it or not. If see an alert box with a message that says you do not have "sufficient" privilege or permission, see the tips in the "Emptying the Trash" section ofthis article.

I finally called Apple suport, and the tech guy told me to change from a secure empty trash to a non secure empty  trash. It worked. Go to finder, preferences, advanced, and uncheck "empty trash securely" Then go to empty trash.

My pleasure beacherteacher12.