Why does Windows 11 Search show web results before my installed apps?

Web results appearing prominently and local files being missing are related search symptoms, but they do not establish a corrupt index. First separate whether the item is missing altogether from whether it ranks below web content.

For missing files, open Windows search indexing settings and check the indexed locations. Classic indexing covers selected folders; add the folder containing your files, or use Enhanced indexing for broader coverage. Allow indexing to finish before testing the same filename again. For installed applications, confirm the app launches outside Search. If it does but Search still fails to find it, end SearchHost.exe in Task Manager; Windows restarts that process when Search is used again.

Indexing changes address coverage, not a guaranteed local-first ranking. I cannot promise a universal switch that removes web results on your unspecified Windows edition. Share the edition, build, and one reproducible app query before considering policy changes.