UI for ASP.NET AJAX: Error thrown after updating from 2013.3.1324.40 to 2014.1.225.40

[Thomas]

I used the Telerik Control Panel to update to 2014.1.225.40.  I opened an existing ASP.NET web application and in Visual Studio 2010 and used the Telerik-->UI for ASP.NET AJAX-->Upgrade Wizard menu item to upgrade the solution.  I left all values on the Solution Upgrade Wizard dialog at their defaults.

After the upgrade, running the project gives the error listed below.  Copying the 2013.3.1324.40 versions of Telerik.Web.UI.dll and Telerik.Web.UI.Skins.dll makes the project run without errors.  We need to either revert our affected projects to the 2013.3.1324.40 versions or know how to eliminate this error with the 2014.1.225.40. 

Error displayed on web page:

Server Error in '/VIMWEBV4_ENT' Application. Telerik.Web.UI.RadWindowManager with ID='RadWindowManager1' was unable to find an embedded skin with the name 'WebBlue'. Please, make sure that the skin name is spelled correctly and that you have added a reference to the Telerik.Web.UI.Skins.dll assembly in your project. If you want to use a custom skin, set EnableEmbeddedSkins=false. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Telerik.Web.UI.RadWindowManager with ID='RadWindowManager1' was unable to find an embedded skin with the name 'WebBlue'. Please, make sure that the skin name is spelled correctly and that you have added a reference to the Telerik.Web.UI.Skins.dll assembly in your project. If you want to use a custom skin, set EnableEmbeddedSkins=false.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:

[InvalidOperationException: Telerik.Web.UI.RadWindowManager with ID='RadWindowManager1' was unable to find an embedded skin with the name 'WebBlue'. Please, make sure that the skin name is spelled correctly and that you have added a reference to the Telerik.Web.UI.Skins.dll assembly in your project. If you want to use a custom skin, set EnableEmbeddedSkins=false.]
Telerik.Web.SkinRegistrar.GetEmbeddedSkinAttributes(ISkinnableControl control, Type controlType, Boolean designTime) +639
Telerik.Web.SkinRegistrar.GetEmbeddedSkinAttributes(ISkinnableControl control, Type controlType) +44
Telerik.Web.SkinRegistrar.RegisterCssReferences(ISkinnableControl _control) +389
Telerik.Web.UI.RadWebControl.RegisterCssReferences() +82
Telerik.Web.UI.RadWebControl.ControlPreRender() +71
Telerik.Web.UI.RadWindowManager.ControlPreRender() +786
Telerik.Web.UI.RadWebControl.OnPreRender(EventArgs e) +47
System.Web.UI.Control.PreRenderRecursiveInternal() +83
System.Web.UI.Control.PreRenderRecursiveInternal() +168
System.Web.UI.Control.PreRenderRecursiveInternal() +168
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +974

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17929

[Slav]

Hello Thomas,

It is possible that the Telerik.Web.UI.Skins assembly is not updated, for example if it was locked by some process.

Please check the reference to this assembly in your project in order to verify that it points to a DLL file with the same version as the version of Telerik.Web.UI (2014.1.225.40) and that it points to a valid file at all.

You can also try restarting Visual Studio after the update and if the problem persists, remove the reference to Telerik.Web.UI.Skins and manually create a new reference to the correct file and then restart Visual Studio again.

The following help article contains information about this error so I would suggest checking it as well: http://www.telerik.com/help/aspnet-ajax/introduction-troubleshooting-skins.html

Regards,
Slav
Telerik