I was just looking at setting up Mercurial on my Windows Home Server and found some good blog articles. My first one was on Jeremy Skinner’s blog here which shows how to configure it under CGI on IIS 7. I’d like to run it as an ISAPI extension though since that would be much faster, I then found this blog article from Matt Hawley which shows how to configure Mercurial as an ISAPI extension under IIS 7.

The final blog article was from another Matt here that shows how to install it under IIS 6. Now I’d already figured out most of this but I was looking for more info because of a little problem, I kept getting 404 errors whenever I accessed the URL. I couldn’t see anything wrong….

Eventually after much wailing and gnashing of teeth I realised my stupidity in a real DOH! moment. I thought I’d share this though since you might also come across this one. I forgot the with IIS 6 it will by default block all ISAPI and CGI extensions unless they are explicitly added into an allow list. I’d forgotten to add the Mercurial DLL into the list. A quick trip to the IIS admin console and the web service extensions section, add in the _hgwebdir_wsgi.dll as an allowed extension and all is now well. Hours wasted to a silly mistake, will remember that one for a while!

Originally posted by Robert Garfoot on 4th May 2010 here http://www.garfoot.com/blog/archive/2010/05/04/setting-up-mercurial-under-iis-6.aspx