While I was updating my blog recently with the latest version I ran into a perplexing error "Root Element is Missing" when trying to hit the blog after the upgrade. The web.config file looked fine, the permissions were set right on all of the folders for both IIS and file permissions. It turns out that when I copied the website up to my host about 3 files came up empty, one of them being the Web.sitemap file. Evidently, when that file is empty and the web.config file is setup for sitemaps it can trigger this error. After getting the proper files up on the host everything was resolved.