Mac OS/X: cannot authenticate / make changes to preferences

Hi --

I am having the same problem as listed here in this post, but that post is from 2012 and refers to a different version of SAV and Mac OS/X:

openforum.sophos.com/.../true

I was not able to find a way to continue this thread, hence this new post.

When opening the preferences and clicking the lock to make changes, the label and lock seem to blink, but no authentication dialog is presented, and therefore no changes can be made.

I am running SAV v9.0.11, on Mac OS/X v10.9.2

Any suggestions?

J.