Active Alerts Views are empty

This came up on the technet forums a while back and I saw it again on a customer site recently which reminded me that I wanted to post about it. Basically, after upgrading to CU3, the Active Alerts views are empty. If you scope the view for selected groups then alerts will appear but as soon as you change it back to “All groups” the alerts disappear.

Resolution? When you install CU3, remember to run the required SQL scripts against the Operations Manager database and datawarehouse!