OneNote is not indexing.

Recently switched computer at work and moved over my OneNote files. However seems I have lost the ability to search within OneNote.

From what I can see Indexing Options is doing one thing right. It has the .One extension set to Index Properties and File Contents. However I would have expected "Microsoft One Note" to appear under this list.

Not sure how to manually add OneNote to the list. Assuming that is even the issue. I could just rebuild the index but that seems useless since it does not to have it as a listed option.

I tried updating the location and rebuilding the index, it took all day, and didn't resolve my issue. I then tried renaming the cache folder and it worked right away.

1. Close OneNote
2. Go to C:\Users\USERNAME\AppData\Local\Microsoft\OneNote\16.0
3. Rename the cache folder to something else like cache.old
4. Open OneNote. It may take a couple minutes to rebuild the cache

Answer found at: https://www.nextofwindows.com/how-to-quickly-fix-onenote-2016-search-stopped-working-issue

1. Go to "Control Panel" -> "Indexing Options"
2. Select "Microsoft OneNote" -> "Advanced"
3. Press "Rebuild"

All you need to do is to rebuild the index, a solution comes from this thread:

I was able to fix my OneNote 2013 search issues on Windows 7 x64 by doing the following:

1. Click Windows Start
2. Type "Indexing Options"
3. Select "Advanced"
4. Select "File Types" tab
5. Scroll to OneNote extensions and ensure they are checked (one, onePkg, oneToc, and oneToc2). I'm not sure if you'll have all of these or not, but won't hurt to make sure.
6. Select "Index Settings" tab
7. Click "Rebuild" button - this may take a while to complete, but my OneNote search began working like new within 10-15 minutes of this.

Now, I don't make any guarantees. These are simply the steps I took and my OneNote is searching again like a champ. I hope you get the same mileage.

Here is a solution that worked for me.
Clearing the cache did not resolve my issue where I could not search OneNote.

Switch to another notebook in OneNote - then switch back.

It appears that this will cause a reindex of the notebook and will reset the cache. I have done this each time the search stops working and it resolves the problem. It would be good to know why the cache / index stop working or gets corrupt in the first place. It would be nice if Microsoft would provide a button that could be clicked to rebuild the index.