Some error messages look complex but some time simple solution can fix it. In this article i am going to explain one of the simple solutions which worked for me to fix SharePoint Designer Error when Designer was complaining, it does not support editing non-SharePoint site.
It happened after installing SharePoint Designer 2010 when i was trying to open a SharePoint 2010 Team Site. The exact error message was: “Microsoft SharePoint Designer does not support editing non-SharePoint sites.”
Microsoft’s KB describes a way to fix this, but I had already performed the step in this KB through SharePoint 2010 Central Admin. but error message persisted in SharePoint Designer 2010.
Guess What fixed the issue? Simply closing SharePoint Designer and then reopening it :)