atomsite.net

There is a problem with categories and AtomPub in the latest Release Candidate of Windows Live Writer. Unfortunately, there is no straight forward way to reproduce the "Null category scheme not supported" error.

System.ArgumentException: Null category scheme not supported
   at WindowsLive.Writer.BlogClient.Clients.AtomProtocolVersion.Atom10ProtocolVersion.CreateCategoryElement(XmlDocument ownerDoc, String category, String categoryScheme, String categoryLabel)
   at WindowsLive.Writer.BlogClient.Clients.AtomClient.Populate(BlogPost post, Uri documentUri, XmlElement node, Boolean publish)
   at WindowsLive.Writer.BlogClient.Clients.AtomClient.EditPost(String blogId, BlogPost post, INewCategoryContext newCategoryContext, Boolean publish, String& etag, XmlDocument& remotePost)
   at WindowsLive.Writer.BlogClient.Blog.EditPost(BlogPost post, INewCategoryContext newCategoryContext, Boolean publish)
   at WindowsLive.Writer.PostEditor.UpdateWeblogAsyncOperation.DoWork()
   at WindowsLive.Writer.CoreServices.AsyncOperation.InternalStart()

I contacted Joe Cheng about the problem and he replied with:

Can you try adding scheme="" to your <categories> element? I know that is a little weird.

If you'd rather not do that, you can create a wlwmanifest.xml file with the following contents:

<?xml version="1.0" encoding="utf-8" ?>
<manifest xmlns="http://schemas.microsoft.com/wlw/manifest/weblog">
 <options>
  <categoryScheme />
 <options>
</manifest>

I've added this to the wlwmanifest.xml file that is available for each collection.  I believe it has fixed the problem but I won't be sure until I've done more testing.

I just wanted to get this out there in case others are having the same issue.