I'm not 100% clear on this. I'm not sure if you are experiencing a bug or you want to increase your index, so I'm going to provide both options here:
- You should be able to fix your issue by incresing your Windows Indexing. You can do this by a) hitting the Windows key followed by searching for 'Indexing Options', b) from there click 'Modify', c) tick the box for 'Local Disk (C:)', and d) click 'OK'. Then close the Indexing Option window and you may need to wait a good 30 minutes for the index to rebuild.
Also, you may want to 'Rebuild' the index through the advanced options (cleaner) which will prompt you with a message stating that "Rebuilding the index might take a long time to complete...". I'd recommend doing it but it will take longer, but if you don't and run into issues try it and click 'OK' to the message.
Note: You may also want to enable 'Treat similar words with diacritics as different words' in the advanced options, but this is a preference thing as it is more like searching the web.
- If Cortana isn't working properly, see article: Windows 10 Search can't find ANY applications. Even calculator
Reinstalled Cortana using the following procedure:
- Open an elevated Command Prompt window (press Win+X, and then press A)
- Type start powershell and press enter
Run the command (in one line):
Get-AppXPackage -Name Microsoft.Windows.Cortana | Foreach
Hope this helps and Good Luck!