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Assume that you have Microsoft Visual Studio 2010 and the Microsoft .NET Framework 4 installed on a computer. You run a Microsoft Build Engine (MSBuild) command that uses the /maxcpucountoption or theĀ /m option to build multiple projects in parallel. For example, you run the following command:

msbuild project name.csproj /maxcpucount:3

Note Each project that you build has many project references.

In this situation, the MSBuild.exe process stops responding. Specifically, CPU utilization reaches 100 percent if one of the projects that you build has a method that contains a loop.


Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft website: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.


To apply this hotfix, you must have the .NET Framework 4 installed.

Restart requirement

You have to restart the computer after you apply this hotfix if the affected files are being used.
We recommend that you close all .NET Framework applications that lock or use the affected files before you install the hotfix.

File information

The global 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.

For all supported versions of the .NET Framework 4 for Windows Server 2003, for Windows XP, for Windows Vista, for Windows Server 2008, or for Windows 7

File name

File version

File size










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 MSBuild command line, visit the following MSDN website:

General information about the MSBuild command lineFor more information about how to build multiple projects in parallel, visit the following MSDN website:

General information about how to build multiple projects in parallel

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