Today I installed the May CU on a SharePoint 2013 farm hosted in Azure. After the Installation was done (with a PowerShell script that disables some services to speed up the process), there were Exceptions opening the User Profile Service (UPS) settings page. So I investigated the logs and found many entries about “Access Denied”. Some directly pointed to the registry hive “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\15.0” with the message Requested registry access is not allowed.
If you are indexing you DFS with SharePoint 2007/2010, you should take a look at this hotfix http://support.microsoft.com/kb/967671. It addresses this issue “When you crawl the file shares in Microsoft Office SharePoint Server 2007 or Microsoft SharePoint Server 2010, you experience poor performance”.