We sometimes get asked if the Microsoft .NET Framework 3.5 Service Pack 1 is really necessary and what the downside would be of not having it on your SharePoint server.

The reality is that it really is quite necessary. If you don't have the Microsoft .NET Framework 3.5 Service Pack 1 you will be unable to use Charting and Gantt reports. You will also see error messages on any page that has a Gantt report located on it.