There are multiple reasons why the
System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. -
System.InvalidOperationException: Stack empty.
Microsoft.VisualStudio.Web.PageInspector.Runtime.WebForms.SelectionMappingRenderTraceListener.EndRendering(TextWriter writer, Object renderedObject)
...
After adding as proposed:
<appSettings>
<add key="PageInspector:ServerCodeMappingSupport" value="Disabled"/>
...
</appSettings>
I noticed I had duplicate selected item on a dropdown list creating the issue.