BITS Behavior

BITS (and thus Windows Update) does not initiate a demand-dial network connection at times when it normally downloads updates. BITS will instead wait for the user or another application to initiate a network connection. If a computer stays disconnected or is otherwise unable to reach its update server for weeks or months at a time, the computer will not have recent updates and might be vulnerable to attack. To mitigate the risk of an unprotected computer spreading worms or viruses on your local network, use NAP.

Note For more information about Network Access Protection, see http://www.microsoft.com/nap/.

BITS stores the partially downloaded files in the destination folder under a temporary name; these files are marked as hidden. When the job is complete, BITS renames the file with its final name and removes the file's hidden attribute. BITS impersonates the job owner before writing these files to preserve the file system security and quotas for the user.