Quick answer: For indexed searches and PPP filters, check that the folder is indexed, its file type has the needed metadata handler or content filter, and the index has finished updating. File Explorer can also search unindexed folders, with behavior depending on search options. Check scope and exclusions before rebuilding the index.
How Windows Search works
Windows Search doesn't look through your whole drive each time you type. It keeps an index — a catalog of file names, properties and, for many file types, the text inside them — and answers your search from that. It's fast, but it only knows about what's in the index.
Almost every "Windows can't find my file" problem comes down to one of the causes below.
1. The folder isn't indexed
By default, Windows indexes your libraries and desktop, not your entire PC. Files on other drives or in folders like C:\Projects aren't in the index.
- Open Settings > Privacy & security > Searching Windows.
- Choose Enhanced to index your whole PC, or keep Classic and add the folders you need.
- Check Excluded folders on the same page, in case the folder you're looking in is excluded.
Searching in a folder that isn't indexed still works in File Explorer, but it's slower and, by default, only looks at file names.
2. Windows isn't searching inside the files
Windows only indexes the text inside a file if it knows how to read that file type. For others, only the name and properties are indexed.
- Open Indexing Options (Settings > Privacy & security > Searching Windows > Advanced indexing options), select Advanced > File Types, and make sure the extension is set to Index Properties and File Contents.
- PDF contents are only indexed when a PDF search filter is installed — Adobe Acrobat Reader includes one, for example.
- For folders that aren't indexed, File Explorer's Folder Options > Search tab has an Always search file names and contents option. It can make searches slow.
3. The index is out of date or stuck
Newly added files can take a while to appear, especially right after copying a lot of files. If files still don't show up, the index may be stuck.
- Check that the Windows Search service is running in Services.
- In Indexing Options, look at the status line — it tells you whether indexing is complete, in progress or paused.
- Still stuck? In Indexing Options, choose Advanced > Rebuild. Rebuilding can take hours on a large drive, and search results are incomplete until it's done.
On laptops, the Respect device power mode settings option on the Searching Windows page can slow indexing down while you're on battery.
4. You're searching for the wrong words
Sometimes the file is indexed but you don't remember its name. File Explorer's search box understands properties, which often works better than guessing names:
kind:=document datemodified:last week— documents you worked on last week.size:>100MB— large files.tags:invoice— files tagged Invoice.ext:.pdf— only PDF files.
More on this: How to find files by tags, ratings, dates and other metadata.
Making files easier to find next time
Search works best when files carry more than a name. Tag+ and Rate+ from Productivity Plus Pack add tags and ratings to many more file types, Comment+ lets you add searchable notes to files, and People+ makes the people in your photos searchable — all through the same Windows Search index.
The one-click filters in the Search filters section in Explorer's navigation pane are Windows searches too, so they follow the same rules: they only find files in indexed locations. After you tag or rate a file somewhere that isn't indexed, Productivity Plus Pack can offer to add that location to the index for you.