I've recently run into a long lasting problem with my Plex Media Server (PMS), where doing any search, be it in the PMS web interface itself, or any of Plex's apps, would always end up with "No matches found." Even if I was looking directly AT matches right on the screen, with my very own eyes (which are still pretty good, I might add, even at my age. ).
Are you getting this error? Probably during the uninstallation of a piece of Adobe software, right?