"Type of file" is part of the problem, I think. I'm a writer, and I not only save the stuff I write, I collect reference material (i.e., I make lots of files) for later use. I am generally searching for a word in a file, often with the page that I know is in my computer in my hand. I'm simply trying to access my own stuff, see. Way too often, the search will not find my document. Windows 98 had an excellent search function, but it has deteriorated almost into oblivion since then. I have actually started keeping paper files on some things, because when I finally run across a file I've been looking for, I have to print it to be able to access it again. So I make a paper file. Yes, computers were supposed to help us stop doing this!
When I change the search criteria from "file" to "document," sometimes it helps, but generally it doesn't. I actually had a Microsoft technician reply to a support request I made on what is the difference between "file" and "document" when you search, and he said he didn't know what I was talking about!!