When we decided to upgrade SharePoint from 2007 to 2010, out IT imposed that the new server would be virtual and our intranet URL and server names will be different too. We went for ‘database attach’ upgrade and almost everything went according to the plan.
It was only after a few days we noticed that the email alerts were not working for everyone. After thorough checking of MS Exchange, anti virus and Windows on the server, we came to a conclusion that only those alerts which were created in the old version were not working.
One option was to write some code and update all the alerts in the application, but luckily we found a better solution from Microsoft, it’s a script which updates all the alerts in an application without sending any notifications to the users. It worked for us.