And suddenly it went wrong. While i was configuring our new enviroment i needed to reboot the server so the latest windows patches where applied. After the system rebooted i went on creating a new site in the sharepoint 2010 enviroment, just clicked siteactions “new site” give it a name and url submit…. wham, “an unhandled exception occured in the Silverlight Application” uh what? The Silverlight interface would’nt submit anymore, not in any site collection. It was possible to create a new site from the “Manage content and structure” so permissions are allright.
After searching the net i found the following solution what solves the issue:
The error appeared after I turned off Security Validation in Web Application General Settings.
Turning it on again fixed the problem.
Well ok i did not turned it on, but it wasn’t enabled. After enabling it “creating sites” worked again from the silverlight interface. The correct location for enabling this is:
Central Administration -> Application Management -> Manage webapplications, select the webapplication and click “General Settings” from the ribbon. Scroll down to “Web Page Security Validation ” (Security validations expire after a configurable amount of time, requiring the user to retry his operation.) Enable it and voila it works again. But what happened in the first place? For testing I turned it off again and site creation via the Silverlight tool fails again so at least it is consistent. After seeing this setting it reminds me to check what kind of time out setting can be made. Because most users have their document open for at least one hour in most cases. I should open a new post for that.