I'm sorry for the error. You are indeed right, the Telerik themes should not require a change to the App_Themes folder permissions. This would be required only when using external themes (not the one, embedded in the Telerik assemblies).
We really think the problem is in not having the Telerik.Web.UI.Skins assembly not referred by the project.
We are uploading a new version of the Telerik Web.UI VSExtensions to the Visual Studio Online Gallery
later today. Can you get the update and try the following steps, please?
- Revert your project to its previous state (using the older RadControls assembly)
- Run the Upgrade Wizard and update the project again.
Let me know if that helps.
the Telerik team
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