A customer of mine has an ASP.NET site that was running fine for years on Windows 2008 R2.
I recently did a Windows Update, and now I am receiving the following error:
Unknown server tag 'cc1:SliderExtender'
I had been using an old version of the ACT from 2011. After replacing the dll with the latest and greatest, the error is the same.
What would be causing this to happen all of a sudden?
NOTE: Any suggestions will not be able to be attempted immediately since it will require contacting my customer and remoting into their server.