I am glad to let you know we were able to fix the issue and uploaded an updated set of VS Extensions in the Visual Studio Gallery:
Telerik WebUI VSExtensions
You should also be able to use the Visual Studio 2010 Extension Manager to download the update.
If you are using Visual Studio 2008 and cannot get updates through the Visual Studio Gallery, you will be able to benefit the update when our next Service Pack release.
@Digno Martinez The most probable cause for the issue you are experiencing is the Upgrade Wizard bug I previously mentioned. There is a high probability that there is nothing wrong with your project or system.
To my regret there are no generic workarounds, besides rebuilding your solution. I would recommend performing a manual upgrade using the instructions in the following help article:
Upgrading RadControls Trial to RadControls Developer license or newer version
All the best,
the Telerik team
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