Searches not finding anything

I can no longer search in EndNote.  It’s ok if I search from within Word, but if I search directly within the EndNote app nothing gets found:  “No matching references found.”

I found an earlier post about this and someone suggested removing the “spotlight” file and then opening the endnote library again.  I don’t seem to have a spotlight file.  

I have a <name> folder, and inside that are four more folders:  pdf, rdb, tdb and trash.  Plus I have a file called <name>library.enl.

I’m using EndNote 6 on one machine, and EndNote 7 on another.  My .enl file is duplicated on both machines and automatically updates (via dropbox) from one machine to the other.

I was searching fine until last week and then suddenly both machines stopped being able to search (right after EndNote crashed on the machine that runs EndNote 7).  I was able to restore my .enl file from a backup but with no searching capabiity.

I gather I need to re-create an index or something like that but am not sure how.