How can I get spotlight to search everywhere for any file? I know for a fact that a file named 1A0CFDAF-E43B-49E1-AC88-CD8CC9146947.jpeg exists in my photo library originals/ subdirectory.  But searching for 1A0CFDAF-E43B-49E1-AC88-CD8CC9146947.jpeg using Spotlight returns no results.  

This is the kind of thing I look for, because if it were obvious I'd already know where it is.  I want to have confidence spotlight is searching everything, so that when I get "no result" I know that means "the file does not exist on your hard drive."  

Is there a way to expand Spotlight's search domain so that it literally indexes my whole drive and finds any and every file, like it really kind of should?
Spotlight doesn't search hidden &amp; system areas at all, by design.

The simplest way to get around this is to use something like EasyFind (freeware) instead. You might need to allow it access to Photos Library, in Privacy and Security preferences. 

It doesn't index, so it's slower than Spotlight, but it will find anything, anywhere.