The type 'Microsoft.Reporting.WebForms.ReportViewer'

The type 'Microsoft.Reporting.WebForms.ReportViewer' exists in both 'C:\Windows\assembly\GAC_MSIL\Microsoft.ReportViewer.WebForms\9.0.0.0__b03f5f7f11d50a3a\Microsoft.ReportViewer.WebForms.dll' and 'C:\Windows\assembly\GAC_MSIL\Microsoft.ReportViewer.WebForms\10.0.0.0__b03f5f7f11d50a3a\Microsoft.ReportViewer.WebForms.dll