ReportViewer Styles and Images Are All Messed Up

Environment

Product	Progress® Telerik® Reporting
Version	Q2 2012 and later
Report Viewers	ASP.NET WebForms Report Viewer

This article relates only to the Legacy Report Viewer. You may be looking for HTML5 Report Viewer Troubleshooting

Solution

To solve the occurred issue:

1. Check if runat="server" is present in the head tag of your web page.

2. Check if the web HTTP handler of your ReportViewer is registered in the web.config file. If the application is deployed on IIS7 and set up to work in the integrated mode, make sure that the preCondition attribute is present at the end of the Telerik.ReportViewer handler:

   <add
       name="Telerik.ReportViewer.axd_*"
       type="Telerik.ReportViewer.WebForms.HttpHandler, Telerik.ReportViewer.WebForms, Version=x.x.x.x, Culture=neutral, PublicKeyToken=a9d7983dfcc261be"
       path="Telerik.ReportViewer.axd" verb="*"
       preCondition="integratedMode"
   />
   

3. Check if the styles of the ReportViewer are registered on the page. This can be accomplished with an HTTP debugging proxy like Fiddler.

4. Check for global styles defined in the application which affect the page with the ReportViewer and conflict with its styles. Remove any style declarations from the page. Make sure the global style rules do not affect HTML elements directly, but are applied through the CssClass property.