Build & Run (or Build) suddenly not working?

Has anybody experienced this problem:

I was building an Android app, had everything configured fine, builds were working okay and transferring directly into my phone for testing...

then, all of a sudden, I try another build and Windows just gives the error "ding" sound. No pop-up message or error messages... nothing. Just won't build.

I tried restarting my computer in case there was an update or something weird, but problem still persisting...

 

Anyway, fixed it... Not sure why, for the first time ever, Unity made no indication that there was a compile error, until I went into the Editor Log to see what was going on...

Super annoying that it made no indication that there were compile errors prior to attempting the build (and no notice of it upon build... until I checked the Editor Log, but I haven't normally had to do that...)

Anyway, hope to get back to using 2017 soon -- this problem was on 5.6.3f1, because I bought Asus Zenfone AR thinking it would be a good "all in one" development device for testing Cardboard, Daydream, and Tango... only to find Tango being deprecated, ARCore not being supported on it (for no apparent reason -- if it works with Tango, it should definitely work with ARCore)... and problems with Tango compatibility on newer versions of Unity. (5.6 seems to be the last version that worked with Tango)

Guess I should have gone with the Galaxy S8 (support for Cardboard, Daydream, ARCore, AND Samsung Gear VR -- seems like the device to get at the moment!)

Literally the worst timing ever to jump into doing some AR dev...

 

how did you fix it