After upgrading SharePoint 2010 Server to the December 2012 CU, Content Query Web Parts will not allow more than one column when grouping. If we select 1 for number of columns, everything works. If we select more than 1, we get an error with a reference GUID.
From the error:
CrossListQueryCache::GetSiteData() - Query: <ViewFields><FieldRef ID="{fa564e0f-0c70-4ab9-b863-0177e6ddd247}" Nullable="True" Type="Text"/><FieldRef ID="{94f89715-e097-4e8b-ba79-ea02aa8b7adb}" Nullable="True" Type="Lookup"/><FieldRef ID="{1d22ea11-1e32-424e-89ab-9fedbadb6ce1}" Nullable="True" Type="Counter"/><FieldRef ID="{28cf69c5-fa48-462a-b5cd-27b6f9d2bd5f}" Nullable="True" Type="DateTime"/><FieldRef ID="{1df5e554-ec7e-46a6-901d-d85a3881cb18}" Nullable="True" Type="User"/><FieldRef ID="{d31655d1-1d5b-4511-95a1-7a09e9b75bf2}" Nullable="True" Type="User"/><FieldRef ID="{8c06beca-0777-48f7-91c7-6da68bc07b69}" Nullable="True" Type="DateTime"/><FieldRef ID="{30bb605f-5bae-48fe-b4e3-1f81d9772af9}" Nullable="True" Type="Lookup"/><FieldRef ID="{ba3c27ee-4791-4867-8821-ff99000bac98}" Nullable="True" Type="Text"/><FieldRef ID="{c5c4b81c-f1d9-4b43-a6a2-090df32ebb68}" Nullable="True" Type="Lookup"/><FieldRef ID="{8fca95c0-9b7d-456f-8dae-b41ee2728b85}" Nullable="True" Type="Lookup"/><FieldRef ID="{39360f11-34cf-4356-9945-25c44e68dade}" Nullable="True" Type="Text"/><FieldRef ID="{543bc2cf-1f30-488e-8f25-6fe3b689d9ac}" Nullable="True" Type="Image"/><FieldRef ID="{43bdd51b-3c5b-4e78-90a8-fb2087f71e70}" Nullable="True" Type="Number"/><FieldRef ID="{9da97a8a-1da5-4a77-98d3-4bc10456e700}" Nullable="True" Type="Note"/><FieldRef ID="{b9e6f3ae-5632-4b13-b636-9d1a2bd67120}" Nullable="True" Type="Computed"/><FieldRef ID="{691b9a4b-512e-4341-b3f1-68914130d5b2}" Nullable="True" Type="Text"/><ProjectProperty Name="Title"/></ViewFields><Lists ServerTemplate="850"></Lists><Webs Scope="Recursive" /><RowLimit>2147483647</RowLimit><Query><OrderBy><ProjectProperty Name="Title" Ascending="TRUE" /></OrderBy></Query> Url: /EN/CP/Dev. Web Part title: Content Query
Error while executing web part: System.ArgumentNullException: 'name' argument cannot be null. Parameter name: name at System.Data.DataColumnCollection.get_Item(String name) at System.Data.DataRow.GetDataColumn(String columnName) at System.Data.DataRow.get_Item(String columnName) at Microsoft.SharePoint.Publishing.WebControls.ContentByQueryWebPart.CalcNumGroups() at Microsoft.SharePoint.Publishing.WebControls.ContentByQueryWebPart.AddContentQueryData() at Microsoft.SharePoint.Publishing.WebControls.ContentByQueryWebPart.GetXPathNavigator(String viewPath) at Microsoft.SharePoint.WebPartPages.DataFormWebPart.PrepareAndPerformTransform(Boolean bDeferExecuteTransform)
Any thoughts?