One of the breaking changes which was made with the 1.0 release of the Microsoft Ajax Extensions was the renaming of the 'Debug' class to 'Sys.Debug' for reasons of compatiability with other frameworks. Breaking changes like this can often be a source of frustration, however today I was pretty glad that they renamed the class, as it helped me to troubleshoot issues with the awful MSI on a Vista development box.
This is what the contents of that directory should look like:
This seems to be the less common reason for the Sys.Debug error, and seems a pretty obvious thing to look at after having found it. However when your Programs and Features list shows up as having the right version, and you've uninstalled/reinstalled/rebooted/cleared cache many times, you don't always think to double check inside the actual directory to make sure that the installer is actually doing what it's supposed to. This is the second time in 2 weeks that I've had problems with a Microsoft packaged MSI. While I'm starting to feel like something of an expert at fixing problems like this, it never feels like an overly productive way to spend my time..
Tags: ASP.NET, AJAX