I was thinking the same thing too... 4 M ?
Try closing down and restarting the program, check to see if the person has gone, if not try deleting again.
I have never had this problem with Roots Magic, and I have been using it since 2003 ( now using the latest version)
As a last resort, go back to previously saved dataset, assuming you do a backup after closing very time you are working on your tree. Hopefully not too much work to reenter