An update package that includes BITS 2.0 and WinHTTP 5.1 is available for Windows Server 2003, for Windows XP, and for Windows 2000

An update package that includes BITS 2.0 and WinHTTP 5.1 is now available for Microsoft Windows Server 2003, for Microsoft Windows XP, and for Microsoft Windows 2000. This package updates BITS to version 2.0 and updates WinHTTP 5.1. These updates help guarantee an optimal download experience when you use future versions of the Automatic Update service, of Microsoft Windows Update, and of other programs that rely on BITS to transfer files by using idle network bandwidth.

These updates for BITS and for WinHTTP 5.1 are required components for the new releases of Windows Update and of Automatic Update. BITS 2.0 improves transfer speeds, improves resiliency, and reduces network bandwidth consumption when it transfers files. The new features of BITS 2.0 work with the user identity and isolation optimizations that are included in the WinHTTP 5.1 update to help improve the security and flexibility of data transfers that use BITS.

BITS 2.0

BITS 2.0 is a Windows system component that provides concurrent foreground and background file transfers. These file transfers include uploads and downloads. BITS uses idle network bandwidth to complete file transfers. BITS 2.0 is used to transfer files by the Automatic Update service, by Windows Update, and by other programs. The features of BITS 2.0 include support for file range download, support for the server message block (SMB) protocol, the ability to limit bandwidth usage, and concurrent foreground file transfers.

BITS 2.0 transfers files between a client and a server. It also returns progress information to the client for file upload and file download operations. BITS 2.0 provides the following features:

• It performs concurrent foreground downloads.
• It supports the SMB protocol for remote names.
• It supports file range download. File range download lets a program change the transfer source of a file.
• It improves client bandwidth consumption.

BITS 2.0 provides queue management of file transfer requests from multiple programs based on priority levels that are indicated by the requesting programs. BITS 2.0 concurrent foreground transfer supports transferring files from multiple jobs using full bandwidth and supports background transfer using only idle bandwidth. If the file transfer process is disrupted, BITS can resume the file transfer from the exact point of interruption instead of retransferring the whole file. Because BITS restarts transfers from the exact point of interruption, all transfers are resumed efficiently when disruptions such as network disconnections and computer restarts occur.

Improvements were made to BITS 2.0 that make sure that the service starts and stops reliably when programs that use layered service providers are present on the system. Programs that use layered service providers include some third-party firewall programs.

BITS 2.0 transfers files more efficiently while throttling bandwidth consumption over slow connections. BITS 2.0 also offers improved throttling support in Kerberos authentication environments. For more information about the new BITS 2.0 functionality and the changes that are made to BITS 1.0 and 1.5 when you install this update, click the following article number to view the article in the Microsoft Knowledge Base:

WinHTTP 5.1

WinHTTP provides an API that supports the HTTP/1.1 Internet protocol. WinHTTP is designed for use by server applications that communicate with HTTP servers, with system services, and with HTTP-based client applications. BITS uses WinHTTP to send HTTP requests and process responses.

The update to WinHTTP 5.1 includes the following improvements:

• Improvements that help identify a user who initiates a file transfer.
• Improvements that help isolate connections that are authenticated to a particular user. This helps prevent identity spoofing by another user.
• Improvements that help make sure that your security policy is enforced when a user communicates with a proxy server.

How to download and install the update package that includes BITS 2.0 and WinHTTP 5.1 for Windows Server 2003

Note If you have disabled the BITS service on your computer, the BITS service is automatically enabled when you install BITS 2.0.

BITS 2.0 and WinHTTP 5.1 are packaged together in the update that is named KB842773. To download and install KB842773, visit the Microsoft Windows Update Web site: Administrators can also download this update from the Microsoft Download Center.

The following file is available for download from the Microsoft Download Center:
For more information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: 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.

Administrators can also deploy this update by using Microsoft Software Update Services (SUS). For more information about SUS, click the following article number to view the article in the Microsoft Knowledge Base:

How to download and install the update package that includes BITS 2.0 and WinHTTP 5.1 for Windows XP

Note If you have disabled the BITS service on your computer, the BITS service is automatically enabled when you install BITS 2.0.

BITS 2.0 and WinHTTP 5.1 are packaged together in the update that is named KB842773. To download and install KB842773, visit the Microsoft Windows Update Web site: Administrators can also download this update from the Microsoft Download Center.

The following file is available for download from the Microsoft Download Center:
For more information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: 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.

Administrators can also deploy this update by using Microsoft Software Update Services (SUS). For more information about SUS, click the following article number to view the article in the Microsoft Knowledge Base:

How to download and install the update package that includes BITS 2.0 and WinHTTP 5.1 for Windows 2000

Note If you have disabled the BITS service on your computer, the BITS service is automatically enabled when you install BITS 2.0.

BITS 2.0 and WinHTTP 5.1 are packaged together in the update that is named KB842773. To download and install KB842773, visit the Microsoft Windows Update Web site: Administrators can also download this update from the Microsoft Download Center.

The following file is available for download from the Microsoft Download Center:
For more information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: 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.

Administrators can also deploy this update by using Microsoft Software Update Services (SUS). For more information about SUS, click the following article number to view the article in the Microsoft Knowledge Base:

How to remove the update package that includes BITS 2.0 and WinHTTP 5.1 for Windows Server 2003, for Windows XP, and for Windows 2000

To remove the update after it has been installed, follow these steps:

1. Click Start, click Run, type appwiz.cpl, and then click OK.
2. In the Currently installed programs list, click Windows XP Hotfix - KB842773, and then click Remove.
   
   Note Windows Server 2003 Hotfix - KB842773 for Windows Server 2003 and Windows 2000 Hotfix - KB842773 for Windows 2000.
3. Follow the instructions in the Windows XP KB842773 Removal Wizard to remove the update from your computer.
   
   Note Windows Server 2003 KB842773 for Windows Server 2003 and Windows 2000 KB842773 for Windows 2000.
4. After Windows XP KB842773 has been removed, restart your computer.
   
   Note Windows Server 2003 KB842773 for Windows Server 2003 and Windows 2000 KB842773 for Windows 2000.

Administrators can also use the Spunist.exe utility to remove this package. The Spuninst.exe program file is located in the %systemroot%\$NtUninstallKB842773$\spuninst folder. The %systemroot% folder is the folder where you installed Microsoft Windows.

How to verify that the update package that includes BITS 2.0 and WinHTTP 5.1 is installed for Windows Server 2003

To verify that the update is installed, compare the files on your computer with the files that are in the following list. The files are located in the %systemroot%\system32 folder.

Note The qmgr.dll file may also be in the %systemroot%\system32\bits folder.

The English version of this update has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.Alternatively, you can make sure that the update is installed by looking at the registry. To do this, follow these steps.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\HotFix\KB842773
   If the update is installed, the subkey contains an entry that is named Installed that has a value that is set to 1.

How to verify that the update package that includes BITS 2.0 and WinHTTP 5.1 is installed for Windows XP

To verify that the update is installed, compare the files on your computer with the files that are in the following list. The files are located in the %systemroot%\system32 folder.

Note The Qmgr.dll file may also be in the %systemroot%\system32\bits folder.

The English version of this update has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.Alternatively, you can make sure that the update is installed by looking at the registry. To do this, follow these steps.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\HotFix\KB842773
   If the update is installed, the subkey contains an entry that is named Installed that has a value that is set to 1.

How to verify that the update package that includes BITS 2.0 and WinHTTP 5.1 is installed for Windows 2000

To verify that the update is installed, compare the files on your computer with the files that are in the following list. The files are located in the %systemroot%\system32 folder.

Note The qmgr.dll file may also be in the %systemroot%\system32\bits folder.

The English version of this update has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.Alternatively, you can make sure that the update is installed by looking at the registry. To do this, follow these steps.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\HotFix\KB842773
   If the update is installed, the subkey contains an entry that is named Installed that has a value that is set to 1.

Known issues

You experience either of the following issues:

• When you install the BITS 2.0_WinHTTP update, the installation may fail, and the Windows Update.log file contains error 80070643.
• When you try to install the BITS 2.0_WinHTTP update, you receive a "Digital Signature Not Found" error message.

For more information about this issue, click the following article number to view the article in the Microsoft Knowledge Base:

For more information about BITS, visit the following Microsoft Web site: For more information about WinHTTP, visit the following Microsoft Web site:

Fixed issues

Your backup program may fail or incorrectly exclude some files from your backup after you install the BITS 2.0_WinHTTP update.

For more information about this issue, click the following article number to view the article in the Microsoft Knowledge Base: