As you may already know, Windows 10 comes with the ability to index your files so the Start Menu and File Explorer can search them faster. Indexing runs in the background without trying to affect your PC's performance. With Windows 10 Fall Creators Update, improvements made to the Start menu's search algorithm make the OS search, that is, Cortana, track and index file system changes almost instantly.
A new feature was highlighted by Microsoft's Jen Gentleman. A GIF animation shows how an .exe file stored in the Desktop folder appears in the search results with its new name right after it is renamed.
The ability to track changes to shortcuts and the Start menu is not new to Windows 10. It was already present with Windows NT's Distributed Link Tracking service. Also, the new Windows Search indexer replacing the legacy indexing service of Windows 2000, was introduced with Windows Vista and significantly improved in each subsequent release so the changes were tracked instantly and showed up in the Start menu. However, Cortana's search algorithm was not up to the mark and often missed some files. Now Cortana's search feature has slightly been reworked in the latest OS version.
Here is the GIF animation I am talking about (via Deskmodder.de).
— Jen Gentleman 🌺 (@JenMsft) November 3, 2017
Here, on Winaero.com, we have a number of useful articles related to Search Indexing in Windows 10.
We have covered how to change the search index location in Windows 10. This can be useful if you have an SSD and want to reduce its write cycles.
You can configure Search Indexing to include files on network shares.
Finally, you can disable Search Indexing if you find no use for this feature.