Error Upgrading to 4.7.2 - Object Reference issue

I've been running 4.7.1 for months now without issues.  Today I upgraded to 4.7.2, worked through a few pesky errors regarding the many packages I have installed but still cannot seem to load pages.  Below is the stack trace.  I have doubled-checked my macros from the backend and they all compile OK.  Where to begin?

using:ASP.NET 4.0, IIS-7

[NullReferenceException: Object reference not set to an instance of an object.]

   umbraco.cms.businesslogic.macro.MacroModel..ctor(Macro m) +13

   umbraco.macro..ctor(String alias) +164

   umbraco.presentation.templateControls.Macro.CreateChildControls() +1285

   System.Web.UI.Control.EnsureChildControls() +102

   umbraco.presentation.templateControls.Macro.OnInit(EventArgs e) +34

   System.Web.UI.Control.InitRecursive(Control namingContainer) +140

   System.Web.UI.Control.InitRecursive(Control namingContainer) +311

   System.Web.UI.Control.InitRecursive(Control namingContainer) +311

   System.Web.UI.Control.InitRecursive(Control namingContainer) +311

   System.Web.UI.Control.InitRecursive(Control namingContainer) +311

   System.Web.UI.Control.InitRecursive(Control namingContainer) +311

   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +480