I was wondering lately how come that search doesn't return any OneNote documents, even though they are saved on our Intranet.

I started looking around and found out that you have to register OneNote iFilter separately. IFilter comes with installation of OneNote client on an Index Server.

Than, you have to register a new File Type in Shared Service Provider.

 

 Once you do that, you have a new file extension registered in you shared Service provider and SharePoint can now crawl this content.

 

If you want your Crawler to crawl also content of your OneNote notebooks you have to write some registry entries. the easiest way is to open a notepad and copy the content of this picture.

 

You can save file as onenote.reg and run it. you will have to restart you computer and run a full crawl for your OneNote notebooks to appear in search results.

Voilà!

Enjoy!