We are sorry for the inconvenience.
This error might be caused by corrupted distribution (the version of Telerik UI for ASP.NET you try to upgrade to). I suggest you to delete this distribution and give the upgrade wizard another try. If you download it through the Visual Studio extensions (see the attachment) it most probably is located here:
If you have used an installer - a repair of the installation may be required.
Please let me know if that is the case or if you require additional guidance.
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