Thank you for contacting us.
This most probable reason why you get this error is partially/wrongly updated assembly files. Visual Studio designer is trying to use the old trial assemblies but it could not find them and that is why you receive the error message.
Depending on the type of Project you are working on there are some steps you could follow:
- If you are using project type WebSite simple replace of the DLLs in the Bin folder should do the trick, however if you have referenced the DLLs globally in Web.config file you should make correction to the linked version too.
- If the project is of type WebApplication, you should reference the DLL files and additionally to replace the DLL file in the Lib and Bin folders of your project.
Beside these specific to the type of project steps, there are two common steps that should be done in order to verify that all references are replaced. First close all opened instances of Visual Studio and then clear the content of these folders:
- C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files
Additionally you could check what is the version of the Telerik assembly which is referenced in the GAC if you have installed it in the GAC. You could check this
help topic for more information.
Give these suggestions a try and let me know if you need further assistance.
All the best,
the Telerik team
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