April 2012 CU - Recall

A regression has been discovered in the April 2012 CU that may result in inaccessible list items, lists, webs and/or site collections within SharePoint. Microsoft is in the process of recalling the CU from the hotfix server, additional information will be provided as it becomes available.

http://blogs.technet.com/b/steve_chen/archive/2012/04/25/3494397.aspx