If you use a plugin like <a href="https://wordpress.org/extend/plugins/private-wp/" rel="ugc">Private WP</a> to make your blog available only to 
registered users, then the auto-configuration ability of Windows Live Writer no longer works for your blog. To make Windows 
Live Writer work again, install this plugin. It will make sure that the configuration files for Windows Live Writer are linked 
from the login page, which does the trick.

WLW Login

Includes the Windows Live Writer manifest link on the login page also, for secured blogs.

codelizard

Have you ever looked at the RSS feed and seen an entry that you didn’t recognize staring you back in the face?
Temporary Post Used For Theme Detection (aaaa0000-abcd-1234-4321-a1b2c3d4e5f6 – xxxxxxxx-aaaa-2222-aaaa-a1b2c3d4e5f6)
Temporary what? I don’t see this post on my live site! What is it??
If you’re a user of Windows Live Writer (which, by the way is an EXCELLENT wysiwyg for blogging), then the answer is right 
in front of you.
Windows Live Writer, in order to give the best quality possible, needs to detect the theme information for your blog. The 
way it does this is to create a temporary blog post, read it really quick, then delete it again right away. The problem is, 
sometimes the posts don’t get deleted. Worse yet, they may be picked up by RSS readers or indexed by an external source 
(feedburner, anyone?) before it manages to be deleted.
So while it needs to be done, it can also be a pain in the backside.
Live Writer Stealth solves this issue. It’s a simple plug-in just to filter out posts from your live blog and RSS feeds that 
match the format of the Windows Live Writer detection messages. This doesn’t break the functionality of WLW, because this 
filter is only applied if you are not signed in as an admin and using Windows Live Writer. Users and RSS viewers, however, will be none-the-wiser.

Live Writer Stealth

Live Writer Stealth keeps those pesky Live Writer test posts from appearing on your site or in your RSS feeds.

WLW Login vs Live Writer Stealth