After you install certain Microsoft security updates, you are prompted to restart the computer. In this situation, make sure that you immediately perform the restart operation. By doing this, you make sure that the computer is updated and that it can immediately use the newly protected and newly installed files. This advice applies not only to individual computers but also to intranet and corporate installations.

Although the update download process and the update installation process are distinct activities, a computer restart is basic to the update installation process. A security update that requires a computer restart does not offer protection against the vulnerability in question until the computer is restarted.

Frequently a system file or a program file can be updated only when the file is not being used or is not in a locked state. Also, certain updates require that you restart the computer before the installation process is 100-percent completed. In this situation, a client computer that has been updated but not yet restarted is in an intermediate state that is neither fully updated nor in its pre-update state. In this intermediate state, some files may have been overwritten, added, or updated. Other files may be locked or protected because of other conditions, such as system-level usage. None of these files can be updated or protected until the computer is restarted.

For those updates that require a computer restart, any vulnerability that is corrected by the update remains uncorrected until you restart the computer. Additionally, in this situation, the process that detects whether any other updates are required does not run until you restart the computer.

For more information about how to manage updates on computers that use automated policies, visit the following Microsoft TechNet Web site: