If you see either DTD (Not Loaded) or Well-Formed XML (Not Loaded) in the drop-down list, select the appropriate document type anyway, and you will be guided through the process of installing the missing DLL. I have done this recently after a clean install at a customer. The result was not as expected. Sometimes even when you have installed the missing DLL’s via InstallDTD.vbs and InstallWFX.vbs, you will still get DTD (Not Loaded) or Well-Formed XML (Not Loaded). The unexpected issue is where this blog post is about.
Double click both files (InstallDTD & InstallWFX) and restart Visual Studio. I still got DTD (Not Loaded) or Well-Formed XML (Not Loaded).
The problem were not enough rights on the current account. Run a command prompt as an administrator.
Go to the location of the files InstallDTD.vbs & InstallWFX.vbs.
Type InstallDTD.vbs and
Type InstallWFX.vbs and
Type Exit and
Restart Visual Studio, you will now see the DTD Schema and the Well-Formed XML loaded.