Ever since upgrading to Windows 10, updates routinely fail for Norton Security. Restarting the PC and attempting to update a second or third time normally would allow updates that had previously failed to be installed correctly. However, today's (8/14/2015) updates aren't installing no matter what I try. The updates that are failing are Norton Web Protection Definitions (considered to be a critical update according to Norton) and the Norton Web Protection Definitions (hub) (also marked as critical).