FIX: Visual Studio 2008 performance decreases when you step through source code that you downloaded from Reference Source Server


In Microsoft Visual Studio 2008, when you step through the source code that you downloaded from Microsoft Reference Source Server, Visual Studio 2008 performance decreases.


This problem occurs because the source files are downloaded again every time that the debugger hits a breakpoint in the code.



Hotfix information

A supported hotfix is now available from Microsoft. But the hotfix is intended only to correct the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Visual Studio 2008 service pack that contains this hotfix. To resolve this problem immediately, visit the following Microsoft Web site: (

Additionally, this hotfix prevents an unnecessary Microsoft Software License Terms dialog box that appears repeatedly when you start the debugger. You can apply this hotfix on 32-bit and 64-bit operating systems. If you apply this hotfix on a 64-bit version of Windows Vista or on later versions of Windows Vista, you create an empty Symsrv.yes text file. Save this file in the folder that contains the Symsrv.dll file. Typically, the Symsrv.dll file is located one of the following folders:

InstallationDrive\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\Remote Debugger\x64
InstallationDrive\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\Remote Debugger\ia64

However, if 32-bit or 64-bit debugging components are copied to a remote computer, you must copy the Symsrv.yes file to the same folder that contains the debugging components. In this scenario, you do not have to apply the hotfix on the remote computer.


You must have Visual Studio 2008 installed to apply this hotfix.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix 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 item in Control Panel.

File name File version File size Date Time File Path
vsdebug.dll 9.0.21022.39 1,513kb 07-Jan-2008 10:57 ..\Program Files\Microsoft Visual Studio 9.0\Common7\Package\Debugger\
symsrv.yes 9.0.21022.39 1kb 13-Dec-2007 02:33 ..\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\Remote Debugger\x86\
symsrv.yes 9.0.21022.39 1kb 13-Dec-2007 02:33 ..\Program Files\Microsoft Visual Studio 9.0\Common7\x86\


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the “Applies to” section.


For more information about the integrated Visual Studio 2008 debugging support, visit the following Microsoft Web site: (


Microsoft Visual Studio 2008 Professional Edition
Microsoft Visual Studio 2008 Standard Edition


Microsoft Knowledge Base Article

This article contents is Microsoft Copyrighted material.
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