Redistributable Visual C++ Files and Licensing

Redistributable Visual C++ Files and Licensing .When you deploy an application, you must also deploy the files that are required to support it. If any of these files are provided by Microsoft, check whether you’re permitted to redistribute them. You’ll find a link to the Visual Studio license terms in the IDE. Use the License terms link in the About Microsoft Visual Studio dialog box. Or, download the relevant EULAs and licenses from the Visual Studio License Directory.

To view the “REDIST list” that’s referenced in the “Distributable Code” section of the Visual Studio 2022 Microsoft Software License Terms, see Distributable code files for Microsoft Visual Studio 2022

Locate the redistributable files

To deploy redistributable files, you can use the redistributable packages installed by Visual Studio. In versions of Visual Studio since 2017, these files are named vc_redist.arm64.exevc_redist.x64.exe, and vc_redist.x86.exe. In Visual Studio 2015, 2017, and 2019, they’re also available under the names vcredist_x86.exevcredist_x64.exe, and (2015 only) vcredist_arm.exe.

The easiest way to locate the redistributable files is by using environment variables set in a developer command prompt. In Visual Studio 2022, the redistributable files are in the %VCINSTALLDIR%Redist\MSVC\v143 folder. In the latest version of Visual Studio 2019, you’ll find the redistributable files in the %VCINSTALLDIR%Redist\MSVC\v142 folder. In both Visual Studio 2017 and Visual Studio 2019, they’re also found in %VCToolsRedistDir%. In Visual Studio 2015, these files can be found in %VCINSTALLDIR%redist\<locale>, where <locale> is the locale of the redistributable packages.

In Visual Studio 2022 and 2019, merge module files are part of an optional installable component named C++ <version> Redistributable MSMs in the Visual Studio Installer. The merge modules are installed by default as part of a C++ install in Visual Studio 2017 and Visual Studio 2015. When installed in Visual Studio 2022, you’ll find the redistributable merge modules in %VCINSTALLDIR%Redist\MSVC\v143\MergeModules. In the latest version of Visual Studio 2019, the redistributable merge modules are in %VCINSTALLDIR%Redist\MSVC\v142\MergeModules. In both Visual Studio 2019 and Visual Studio 2017, they’re also found in %VCToolsRedistDir%MergeModules. In Visual Studio 2015, they’re found in Program Files [(x86)]\Common Files\Merge Modules.

Install the redistributable packages

The Visual C++ Redistributable Packages install and register all Visual C++ libraries. If you use one, run it as a prerequisite on the target system before you install your application. We recommend that you use these packages for your deployments because they enable automatic updating of the Visual C++ libraries. For an example about how to use these packages, see Walkthrough: Deploying a Visual C++ Application By Using the Visual C++ Redistributable Package.

Each Visual C++ Redistributable package checks for the existence of a more recent version on the machine. If a more recent version is found, the package won’t get installed. In Visual Studio 2015 or later, Redistributable packages display an error message stating that setup failed. If a package is run by using the /quiet flag, no error message is displayed. In either case, an error is logged by the Microsoft installer, and an error result is returned to the caller. In Visual Studio 2015 and later, you can avoid this error by checking the registry to find out if a more recent version is installed.

The current installed version number is stored in the HKEY_LOCAL_MACHINE\SOFTWARE[\Wow6432Node]\Microsoft\VisualStudio\14.0\VC\Runtimes\{x86|x64|ARM} key. The version number is 14.0 for Visual Studio 2015, 2017, 2019, and 2022 because the latest Redistributable is binary compatible with previous versions back to 2015. The key is ARMx86, or x64 depending on the installed vcredist versions for the platform. (You need to check under the Wow6432Node subkey only if you’re using Regedit to view the version of the installed x86 package on an x64 platform.) The version number is stored in the REG_SZ string value Version and also in the set of MajorMinorBld, and Rbld REG_DWORD values. To avoid an error at install time, you must skip installation of the Redistributable package if the currently installed version is more recent.

Install the redistributable merge modules

Merge modules (.msm files) for Visual C++ Redistributable files are deprecated. We don't recommend you use them for application deployment. Instead, we recommend central deployment of the Visual C++ Redistributable package. Central deployment by a Redistributable package makes it possible for Microsoft to service runtime library files independently. And, an uninstall of your app can't affect other applications that also use central deployment. When you use a Redistributable package for central deployment, you aren't responsible for tracking and maintaining the runtime libraries. Otherwise, an update to the runtime library files requires you to update and redeploy your .msi installer. Your app could be vulnerable to bugs or security issues until you do.

Redistributable merge modules must be included in the Windows Installer package (or similar installation package) that you use to deploy your application. For more information, see Redistributing by using merge modules. For an example see Walkthrough: Deploying a Visual C++ application by using a setup project.

Install individual redistributable files

It’s also possible to directly install the Redistributable DLLs in the application local folder. The application local folder is the folder that contains your executable application file. For servicing reasons, we don’t recommend you use this installation location.

Potential run-time errors

If Windows can’t find one of the Redistributable library DLLs required by your application, it may display a message similar to: “This application has failed to start because library.dll was not found. Reinstalling the application may fix this problem.”

To resolve this kind of error, make sure your application installer builds correctly. Verify that the Redistributable libraries get deployed correctly on the target system. For more information, see Understanding the Dependencies of a Visual C++ Application.