At the last update on of the DBAs accidently installed both the client tools and the monitoring service to their PC meaning (site configuration) we now had 2 monitoring services running.
We noticed that some of the SQLSentry email alerts were originating from his PC.
I got him to stop the service on his PC so that I could remove it from the list leaving just the original server where the monitoring service has run fine for years.
After this we stopped receiving any emails. When I checked the windows service on the server it had stopped, so I started it. Moments later the status of the service changed from running to stopping. We I look at site config in SQL Sentry I see that under default site the icon (cog) next to the server name is greyed out.
When my colleague restarts the service on his PC it is auto added to the list of monitoring services and emails begin to flow again.
Obviously this is not idea - how can we force SQL Sentry to accept the server as the default/only monitoring service?