Latest Sonar Platinum, 2016.5 build 45, x64.  I deleted a plugin from a track while playing the whole project (including the track I deleted the plugin from) and the progress bar (in the control bar where "Save" progress is shown etc) showed "Reset button" with a completed progress bar, yet with the X at the end (as when canceling is a choice) but after about 15 secs Sonar crashed.  Does anyone know why "Reset button" would be shown there, and what I might have done to prompt it?

Interesting - I had the same 'reset button' notification pop up and Sonar crashed when I was using the playlst function. I had just started a song, so the previously played song was closing and the next was loading.
 
I have ever seen this notification before either, and it is the first time in years that Sonar has crashed on me whilst just playing a song in the playist. 
 
I was using 2016.5 update 1.
 
 

For whatever reason, Cakewalk seems to have put this in as a warning that it's gonna crash due to circumstances beyond it's control.
 
I must admit, seeing "Reset Button" makes me go "aw crap..." and softens somewhat then, the shock of the actual crash dialog that will come in about two seconds after that.
 
Changes not the outcome, in many cases you gonna come out on the short end regardless.
 
It should probably say  "Duck!" or "We're Sorry".
Reset button sounds like a internal debug message they just left in there.
 
I duuno.
 
 

Good to know we are not alone then. The first time it happened I thought I must have hit some new keyboard 'nuke it' shortcut:)
 

I think the bakers should let us change that message string to something snarky of our choice since it has little or no other value to the end user. If for nothing else than personal comedic value.