There is an update to Windows XP and Windows Vista that was probably installed on your machine without you even knowing about it. This update, KB971029, disables the AutoRun feature and provides the user with no file-installation prompts when inserting a USB flash drive.
As Computerworld reports, Microsoft originally deployed this update around February 8th of this year. This patch was set to be an optional update. However, Microsoft now changed its mind by reclassifying this update as “High Priority.” This update is now automatically downloaded via Automatic Updates.
In case you were wondering why, Microsoft decided to disable automatic execution of files via AutoRun or AutoPlay because of malware that has been targeting such methods. A worm called “Conficker” and a worm called “Stuxnet” are two worms that utilize AutoRun to infect machines when a flash drive is plugged in.
Because of this update, anytime a flash drive is plugged in on a machine that runs Windows XP or Windows Vista, an AutoRun popup will not display. This update does not affect CDs or DVDs, but only USB flash drives.
This actually breaks a lot of features that most USB flash drives require in order to function. Microsoft informs XP and Vista users that “Users who install this update will no longer receive a setup message that prompts them to install programs that are delivered by USB flash drives. Users will have to manually install the software.”
If you are on Windows XP or Windows Vista and want to enable AutoRun once again, download this tool available from Microsoft’s website.