I don't typically talk on forum's, I'm usually one just to read them for fixes. But I actually had the same issue as you NOLATechy and had to go through a few different threads to find a fix for it. I went from 10162 to 10166 and had the start menu bug, but still had it after reverting back to 10162. This fix worked for me, hopefully it will work for you. See below.
Open powershell as administrator.
Paste this
$app = Get-AppxPackage -Name Microsoft.WindowsPhone
$app | Remove-AppxPackage
$man = $app.installlocation + "\appxmanifest.xml"
Add-appxpackage -register -disabledevelopmentmode $man
Press enter
Try the start menu now.
It seems that the microsoft phone companion app was causing the problem for me.
Hopefully this helps! Goodluck.