I try to create a new list in SharePoint 2010 with AddGallery.aspx and the Silverlight app gives me

An unhandled exception occurred in the Silverlight Application

right when I click the "Create" button.

Here is some additional info:

  1. Same error across all sites
  2. Same error with all types of lists
  3. Same error with IE8, Chrome and FireFox
  4. Creating the list with SharePoint Designer works fine
  5. I have tried recycling the application pool
  6. It's a fresh Install; there are no custom solutions deployed

I have no idea what could be the source of the problem.

2 Answers 2


The error appeared after I turned off Security Validation in Web Application General Settings.

Turning it on again fixed the problem.


I recently had the need to actually disable the Silverlight UI because I needed to ensure that the security validation setting remained off because of a buggy RSS feed reader, there is a way to ensure that it does not pop up which Adam Macaulay has an excellent post on disabling in more than one way.


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