MSBuild reserved and well-known properties

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MSBuild provides a set of predefined properties that store information about the project file and the MSBuild binaries. These properties are evaluated in the same manner as other MSBuild properties. For example, to use the MSBuildProjectFile property, you type $(MSBuildProjectFile).

MSBuild uses the values in the following table to predefine reserved and well-known properties. Reserved properties cannot be overridden, but well-known properties can be overridden by using identically named environment properties, global properties, or properties that are declared in the project file.

Reserved and well-known properties

The table in this section shows the MSBuild predefined properties. The example column in the table relates to the following example project file, assumed to be located at C:\Source\Repos\ConsoleApp1\ConsoleApp1, and shows the values of these properties have when accessed in the project file, when MSBuild is invoked with no special command-line options, with a preview build of Visual Studio 2019 version 16.7 installed.

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>
</Project>
Property Reserved or well-known Description Example
MSBuildBinPath Reserved The absolute path of the folder where the MSBuild binaries that are currently being used are located (for example, C:\Windows\Microsoft.Net\Framework\<versionNumber>). This property is useful if you have to refer to files in the MSBuild directory.

Do not include the final backslash on this property.		 C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild\Current\Bin
MSBuildExtensionsPath Well-known Introduced in the .NET Framework 4: there is no difference between the default values of MSBuildExtensionsPath and MSBuildExtensionsPath32. You can set the environment variable MSBUILDLEGACYEXTENSIONSPATH to a non-null value to enable the behavior of the default value of MSBuildExtensionsPath in earlier versions.

In the .NET Framework 3.5 and earlier, the default value of MSBuildExtensionsPath points to the path of the MSBuild subfolder under the \Program Files\ or \Program Files (x86) folder, depending on the bitness of the current process. For example, for a 32-bit process on a 64-bit machine, this property points to the \Program Files (x86) folder. For a 64-bit process on a 64-bit machine, this property points to the \Program Files folder.

Do not include the final backslash on this property.

This location is a useful place to put custom target files. For example, your target files could be installed at \Program Files\MSBuild\MyFiles\Northwind.targets and then imported in project files by using this XML code:

<Import Project="$(MSBuildExtensionsPath)\MyFiles\Northwind.targets"/>		 C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild
MSBuildExtensionsPath32 Well-known The path of the MSBuild subfolder under the \Program Files or \Program Files (x86) folder. The path always points to the 32-bit \Program Files (x86) folder on a 32-bit machine and \Program Files on a 64-bit machine.". See also MSBuildExtensionsPath and MSBuildExtensionsPath64.

Do not include the final backslash on this property.		 C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild
MSBuildExtensionsPath64 Well-known The path of the MSBuild subfolder under the \Program Files folder. For a 64-bit machine, this path always points to the \Program Files folder. For a 32-bit machine, this path is blank. See also MSBuildExtensionsPath and MSBuildExtensionsPath32.

Do not include the final backslash on this property.		 C:\Program Files\MSBuild
MSBuildWarningsAsErrors Well-known A list of warning codes to treat as errors. MSB1234;MSB5678
MSBuildWarningsNotAsErrors Well-known A list of warning codes that should not be promoted to errors even if the -warnAsError switch is set to promote all other warnings to errors. Note that it has no effect if that is not true. MSB1234;MSB5678
MSBuildWarningsAsMessages Well-known A list of warning codes to treat as messages. MSB1234;MSB5678
MSBuildInteractive Reserved true if MSBuild is running interactively, allowing user input. This setting is controlled by the -interactive command-line option. false
MSBuildLastTaskResult Reserved true if the previous task completed without any errors (even if there were warnings), or false if the previous task had errors. Typically, when an error occurs in a task, the error is the last thing that happens in that project. Therefore, the value of this property is never false, except in these scenarios:

- When the ContinueOnError attribute of the Task element (MSBuild) is set to WarnAndContinue (or true) or ErrorAndContinue.

- When the Target has an OnError element (MSBuild) as a child element.		 true
MSBuildNodeCount Reserved The maximum number of concurrent processes that are used when building. This is the value that you specified for -maxcpucount on the command line. If you specified -maxcpucount without specifying a value, then MSBuildNodeCount specifies the number of processors in the computer. For more information, see Command-line reference and Build multiple projects in parallel. 1
MSBuildProgramFiles32 Reserved The location of the 32-bit program folder; for example, C:\Program Files (x86).

Do not include the final backslash on this property.		 C:\Program Files (x86)
MSBuildProjectDefaultTargets Reserved The complete list of targets that are specified in the DefaultTargets attribute of the Project element. For example, the following Project element would have an MSBuildDefaultTargets property value of A;B;C:

<Project DefaultTargets="A;B;C" >		 Build
MSBuildProjectDirectory Reserved The absolute path of the directory where the project file is located, for example C:\MyCompany\MyProduct.

Do not include the final backslash on this property.		 C:\Source\Repos\ConsoleApp1\ConsoleApp1
MSBuildProjectDirectoryNoRoot Reserved The value of the MSBuildProjectDirectory property, excluding the root drive.

Do not include the final backslash on this property.		 Source\Repos\ConsoleApp1\ConsoleApp1
MSBuildProjectExtension Reserved The file name extension of the project file, including the period; for example, .proj. .csproj
MSBuildProjectFile Reserved The complete file name of the project file, including the file name extension; for example, MyApp.proj. ConsoleApp1.csproj
MSBuildProjectFullPath Reserved The absolute path and complete file name of the project file, including the file name extension; for example, C:\MyCompany\MyProduct\MyApp.proj. c:\Source\Repos\ConsoleApp1\ConsoleApp1\ConsoleApp1.csproj
MSBuildProjectName Reserved The file name of the project file without the file name extension; for example, MyApp. ConsoleApp1
MSBuildRuntimeType Reserved The type of the runtime that is currently executing. Introduced in MSBuild 15. Value may be undefined (prior to MSBuild 15), Full indicating that MSBuild is running on the desktop .NET Framework, Core indicating that MSBuild is running on .NET Core (for example in dotnet build), or Mono indicating that MSBuild is running on Mono. Full
MSBuildStartupDirectory Reserved The absolute path of the folder where MSBuild is called. By using this property, you can build everything below a specific point in a project tree without creating <dirs>.proj files in every directory. Instead, you have just one project—for example, c:\traversal.proj, as shown here:

<Project ...> <ItemGroup> <ProjectFiles Include="$ (MSBuildStartupDirectory) **\*.csproj"/> </ItemGroup> <Target Name="build"> <MSBuild Projects="@(ProjectFiles)"/> </Target> </Project>

To build at any point in the tree, type:

msbuild c:\traversal.proj

Do not include the final backslash on this property.		 c:\Source\Repos\ConsoleApp1
MSBuildThisFile Reserved The file name and file extension portion of MSBuildThisFileFullPath. ConsoleApp1.csproj
MSBuildThisFileDirectory Reserved The directory portion of MSBuildThisFileFullPath.

Include the final backslash in the path.		 c:\Source\Repos\ConsoleApp1\ConsoleApp1\
MSBuildThisFileDirectoryNoRoot Reserved The directory portion of MSBuildThisFileFullPath, excluding the root drive.

Include the final backslash in the path.		 Source\Repos\ConsoleApp1\ConsoleApp1\
MSBuildThisFileExtension Reserved The file name extension portion of MSBuildThisFileFullPath. .csproj
MSBuildThisFileFullPath Reserved The absolute path of the project or targets file that contains the target that is running.

Tip: You can specify a relative path in a targets file that's relative to the targets file and not relative to the original project file.		 c:\Source\Repos\ConsoleApp1\ConsoleApp1\ConsoleApp1.csproj
MSBuildThisFileName Reserved The file name portion of MSBuildThisFileFullPath, without the file name extension. ConsoleApp1
MSBuildToolsPath Reserved The installation path of the MSBuild version that's associated with the value of MSBuildToolsVersion.

Do not include the final backslash in the path.

This property cannot be overridden.		 C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild\Current\Bin
MSBuildToolsVersion Reserved The version of the MSBuild Toolset that is used to build the project.

Note: An MSBuild Toolset consists of tasks, targets, and tools that are used to build an application. The tools include compilers such as csc.exe and vbc.exe. For more information, see Toolset (ToolsVersion), and Standard and custom Toolset configurations.		 Current
MSBuildVersion Reserved The version of MSBuild used to build the project.

This property can't be overridden, otherwise the error message MSB4004 - The 'MSBuildVersion' property is reserved, and can not be modified. is returned.		 16.11.0
MSBuildAssemblyVersion Reserved The version of MSBuild assemblies used to build the project. 16.0
MSBuildFileVersion Reserved The 4 part version of MSBuild assemblies used to build the project. 16.11.0.30701
MSBuildSemanticVersion Reserved The full semver 2.0 version of MSBuild assemblies used to build the project. 16.11.0-preview-21302-05+5e37cc992

Names that conflict with MSBuild elements

In addition to the above, names corresponding to MSBuild language elements cannot be used for user-defined properties, items, or item metadata:

  • VisualStudioProject
  • Target
  • PropertyGroup
  • Output
  • ItemGroup
  • UsingTask
  • ProjectExtensions
  • OnError
  • ImportGroup
  • Choose
  • When
  • Otherwise

See also