Couldn't find this mentioned anywhere else so thought i better report this here

When deleting a macro (or renaming its alias in fact), that is enabled in a Macro Container render control, this causes *all* Content pages (not just the ones that use the macro container) to fail with the following error:

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

   umbraco.editorControls.macrocontainer.MacroEditor.OnInit(EventArgs e) +693
   System.Web.UI.Control.InitRecursive(Control namingContainer) +142
   System.Web.UI.Control.AddedControl(Control control, Int32 index) +270
   umbraco.editorControls.macrocontainer.Editor.OnInit(EventArgs e) +3241
   System.Web.UI.Control.InitRecursive(Control namingContainer) +142
   System.Web.UI.Control.InitRecursive(Control namingContainer) +390
   System.Web.UI.Control.InitRecursive(Control namingContainer) +390
   System.Web.UI.Control.InitRecursive(Control namingContainer) +390
   System.Web.UI.Control.InitRecursive(Control namingContainer) +390
   System.Web.UI.Control.AddedControl(Control control, Int32 index) +270
   umbraco.controls.ContentControl.addControlNew(Property p, TabPage tp, String Caption) +8984
   umbraco.controls.ContentControl.CreateChildControls() +1415
   System.Web.UI.Control.EnsureChildControls() +145
   umbraco.controls.ContentControl.OnInit(EventArgs e) +152
   System.Web.UI.Control.InitRecursive(Control namingContainer) +142
   System.Web.UI.Control.AddedControl(Control control, Int32 index) +270
   umbraco.cms.presentation.editContent.OnInit(EventArgs e) +2174
   System.Web.UI.Control.InitRecursive(Control namingContainer) +142
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1476

Not that published content pages are not affected.

The workaround is fairly obvious - just take the macro out of the allowed macros in the picker before deleting or whatever - and remember not to do it again ;)  Still probably worth looking at though.

I'm using umbraco v 4.5.2 (Assembly version: 1.0.3891.20719) .Net Version:2.0.50727.5420; Asp.Net Version:2.0.50727.5420

Windows Server 2008R2 SP1 IIS 7

Cheers

Paul