Spotlight doesn't find the contents of at least one file Goal - find a clever way to discover what Spotlight has (or hasn't indexed).

I have an xls spreadsheet that has the names and emails addresses of people who attended a recent course of mine. In the past few weeks I need to search precisely which course someone attended. The person had a unique last name and so I just put the name into spotlight. Nothing found. A few minutes of digging manually confirmed the person had attended the course I expected. 

Related discoveries


none of the contents of that file is indexed by Spotlight - tested by searching other names
older xls files in the same folder are correctly indexed
Searching on the filename finds the file so the file itself is found by spotlight
Copy the column of names to a temp spreadsheet, save them and search - file find
Rebuilding the index from scratch warmed my CPU but didn't change anything
I've checked the simple spotlight preferences - xls spreadsheets aren't ignored 


Since I don't know why its getting missed I'm concerned that other files might not get indexed properly as well.
I would suspect a corrupt file. It may be just damaged enough to stop Spotlight reading it properly.

If you select the file in the Finder and hit the space bar does it open in Quick Look? If it doesn't then it is broken.

Try opening it in Excel and copying and pasting everything into a new file.