There, is a simple workaround for this, See the below Image, And that’s it.
We could not figure out what the error was until we discovered this tip because Visual Studio did not give us any feedback.
The issues are - I have a Ribbon Bar control in an that gets deleted from the each time I save the file.
I "solved" this moving the control declaration in my file - I have several pages hosting different Telerik controls which definition in the files has the case of the tag in the file.
I can temporally solve the problem by removing the Rad AJAXManager and the Rad Script Manager from the master page run the application and then insert the two Telerik components again on the master page.
Then I don't get any errors in design mode until I close the project and open it again. NET guidelines and best practices for dll creation. Can you please try the suggestions provided in Unknown server tag/Could not load file or assembly errors section in this help article? Hi Anders, First, since this is isolated to a certain machine, I would advise comparing some settings/installed software, especially VS plugins to try and find a difference.