I had the same problem just three hours ago. I contacted my host (Bluehost) who restored the site to previous working version and asked me to try again. WHich I did, same problem: under previous dashboard a meaage and link to update wordpress is in the usual place, but after pressing install, the usual script messages that indicate installation is progressing show up – but nothing to indicate the installation is completed – only a blank white page in a browser window (any browser). Re-installing previous workign version by logging in I recieved a wordpress generated error messaeg to the effect the databsae needed to be updated – pressed the button t update , and i was back on the version beofre 4.6. My host suggested I wait for a few dys to see if WordPress came up with a general solution to the problem.
Since my business runs on wordpress i don’t plan to update to the next version until this update is installed AND WordPress developers verfies it works ok – ie seamlessly as WordPress alwasy has for me!