This article describes a prerequisite software update (949939) that applies to the Windows Vista products that are mentioned in the “Applies to” section. This software update is a prerequisite for Windows Vista update 937287. Update 937287 is required to install Windows Vista Service Pack 1 (SP1).
This update helps improve installation reliability when you install Windows Vista update 937287. It contains an update to the Windows Vista installation software. The installation software is the component that handles the installation and removal of software updates, language packages, optional Windows features, and service packs.
If your computer is already running Windows Vista SP1 or if you have already installed update 937287, you do not have to install this update. Also, you do not have to install this update if you are using the Windows Vista SP1 stand-alone package to install update 937287. For more information about the Windows Vista SP1 stand-alone package, see the Windows Vista Service Pack 1 Deployment Guide.To do this, visit the following Microsoft Web site:
This update must be installed on a computer that is running Windows Vista. It cannot be installed on an offline image.
Before you create an offline image, you have to apply both updates. In this case, you must restart the system after you install update 949939 and before you install update 937287. Images that have this update (949939) installed but not update 937287 cannot be serviced offline by using Package Manager.
This update is meant as a prerequisite only for installing update 937287. After you install update 949939 and after you restart the computer, we recommend that you install update 937287.
How to obtain the update
You can obtain update 949939 from Windows Update or from the Microsoft Download Center.
How to obtain update 949939 from Windows Update
Click Start , click All Programs, and then click Windows Update.
In the navigation pane, click Check for updates, and then wait while Windows looks for the latest updates for your computer. If updates are found, install them.
To obtain update 949939, you can also visit the following Microsoft Web site:
For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to obtain Microsoft support files from online services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.
No prerequisites are required to apply this update.
You must restart the computer after you apply this update.
Update replacement information
This update does not replace any other updates.
For more information about update 937287, click the following article number to view the article in the Microsoft Knowledge Base:
937287 A software update is available for the Windows Vista installation software feature