The report definition is not valid

I have converted an .rdlc rerort from SSRS 2005 to SSRS 2008. Now when I am going to build that project I have got error.

The report definition is not valid. Details: The report definition has an invalid target namespace 'http://schemas.microsoft.com/sqlserver/reporting/2008/01/reportdefinition' which cannot be upgraded.

Please give me solution for this.

How do you fix the SSRS error definition of this report is not valid?

Definition of this Report is Not Valid – Solution. There are no tricks to solving this problem. All you need to do is set the RDL to the appropriate version that's supported by your SSRS server.

Just stumbled upon this question since I was having the same problem. In my case, I had a reference to an older version of ReportViewer.WinForms. When I switched versions, everything worked fine. Might not be the same case as yours, but just thought I'd chime in in case anyone else finds this page.