ReportViewer Client Print Control “Unable to load client print control”?

Question

Has anyone come across this issue?

Seems MS have broken it with their own update:

A number of people have reported problems using the Active

Answer 1

I have had the same problem (on several different servers). Applying SP3 and Report Viewer SP1 has helped on some of the servers, allowing the client machines to connect and download the control with no problem. However, I have had one server that, even after applying the updates, when accessing the report viewer using a client machine, it was still giving me the error. On looking into the exact URL GET request that is being sent, I discovered that it is possible to force the client machine to connect directly to the Report Server to download the control.

The user would need to enter the following url:

http://reportservername/Reports/Reserved.ReportViewerWebControl.axd?ReportSession=51bjqv45xydgos2wghu5ceza&ControlID=7617dedbf0234f89b80cad8e64431014&Culture=2057&UICulture=9&ReportStack=1&OpType=PrintHtml

This should then pop up the required download/install prompt.