Fxi Now Button is on.. but what is it going to do?

I made this misake - last time I saw the "Fix Now" button on in NIS 18.7.0.13 (whatever happened to the good ol versions, 2012 etc) - and I thought it would give me a screen or something - telling me what it was going to do to "fix" whatever it wasn't happy with.  It didn't  So I wrote here and asked what it did and was told it's hard to find out after the fact.. SO - this time I haven't clicked the "FIX NOW" button - but I would like to know what it's going to do.  Any advice would be appreciated.  Thank you.