Thread:Project:Support desk/title=Main Page throwing 404 - cannot access MW/reply (2)

This can happen if the main page hasn't been created. MediaWiki sends a 404 response on pages that don't exist, but the contents is like any other page, and it's perfectly normal, unless your IIS server is intercepting the 404 response and sending it's own 404 error page. If that's the case, see this.

If that's not the issue, maybe the installer failed to properly configure $wgUsePathInfo or $wgArticlePath, etc, specially if you have rewrite rules. Check out the error logs of IIS to see what physical path is trying to access and if it really exists.