Which event to look for User Mapping changes We have been having issues where login's are having their user mapping changed unexpectedly and I am looking to have an alert fire off whenever that happens. Is there a way for me to capture that? I have been able to create a trigger for altering a login or changing their server roles, but not the user mapping itself.

Edit 
To be more clear, I am referring to database role memberships for users is what changing unexpectedly.
I found what I was looking for. I needed to check for the trigger event types ADD_ROLE_MEMBER and DROP_ROLE_MEMBER in my trigger at the ALL SERVER level.

I'll leave this up in case anyone else has a better solution