Help: spotlight can't see Firefox in Applications folder? (FYI, I'm using Snow Leopard.)  I used to launch Firefox using spotlight by just typing "Firefox" to locate it.  Since I didn't launch Firefox often, I didn't want it in my dock, so I just got in that habit.

For some reason, starting last week, spotlight can no longer find Firefox.  I type "firefox" and I get results (emails, jar files, and so on), but no Firefox.app.  It's still there, though, sitting my Applications folder and it launches fine when I click on it.

Did I do something to break spotlight?  And how should I fix this?

Thanks, Rob
This has helped on a lot of macOS boxes I've worked on (10.14, 10.15 Catalina beta 1, beta 2, beta 3 and beta 4), perhaps for different reasons now in 2019 than when OP originally asked the question.


Open Terminal/iTerm and run:
sudo xattr -r -d com.apple.quarantine /Applications/Firefox.app
Authenticate with your admin password.


Your download was tagged by a macOS security mechanism as potentially dangerous, so the extended attribute com.apple.quarantine was set.  


Since the OS didn't ask for user confirmation, the xattr was most probably already removed, but only from the top level package Firefox.app itself, but not its contents. 
This is at least one scenario where an App  


can be launched without user confirmation, but 
Spotlight refuse to index. 



See superuser.com/what-should-i-do-about-com-apple-quarantine for more.