Handler could not be removed?

Wonderful plugin…

and, when I update, I continually get a popup
window that reads “Handler Could Not Be Removed”

Very, Very, Very annoying when editing the site
since it pops up at just about any action taken.

We had to go back to a previous version to prevent
the popup….

if you are able to address the issue, it will be
GREATLY appreciated.

thank you kindly