Redistribution rights for MSVC runtime code with Visual Studio Community 2026 (/MT, ONNX Runtime, NumPy)

Question

Hello,

I am an individual developer using the free Visual Studio Community 2026 edition to develop and maintain a paid Windows desktop application.

Before adding new native dependencies to an existing commercial application, I would like to clarify the applicable Microsoft licensing and redistribution terms for Microsoft Visual C++ runtime code in several specific cases.

I have already contacted Microsoft Support. I was advised that free Visual Studio Community users generally use public documentation, Microsoft Q&A, Developer Community, and other community support channels, and that there does not appear to be a dedicated support channel for individual licensing determinations for free Community users.

I understand that Microsoft Q&A cannot provide legal advice. I am therefore looking for clarification based on Microsoft's published Visual Studio license terms and REDIST documentation, ideally with links to the applicable official provisions.

Environment

Visual Studio Community 2026

MSVC 14.44 / v143 toolset

Windows x64

Individual developer

Existing paid Windows desktop application

Question 1 — CRT statically linked into my own /MT binaries

If I build my own DLL or PYD files using the MSVC toolset supplied with Visual Studio Community 2026 and compile them with /MT, Microsoft CRT code becomes statically linked into the resulting binaries.

Am I permitted to redistribute those completed DLL/PYD binaries as part of my paid application?

I am not redistributing Microsoft's original .lib files themselves, only my final compiled binaries that contain statically linked CRT code.

If this redistribution is permitted, which Visual Studio license term or REDIST provision grants that right?

Thank you.

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<モデレーター注>
質問は、第三者を含めて混乱しない様に、一問一答形式にしてください。
1つのスレッド内に複数の質問を投稿しない
回答内容が発散してしまうことを回避する為に、複数の質問内容は削除させて頂きました。

Answer 1

前提として以降の文章はMicrosoftの公式な見解ではない

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個々のlibがどのようなライセンスで使用または配布できるかを個別に考える必要があります。 WindowsSDKのlibでは可能でも、ほかのlibはダメだということも当然ある。

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WindowsSDK付属のlibならWindowsSDKのライセンス Windows SDKをインストールしようとすると表示されるダイアログにあるLicenseAggreementを読みましょう。(表示中に%temp%を漁るとlicense.rtfが得られます)
あるいはインストール後なら%ProgramFiles(x86)%\Windows Kits\10\Licenses

license.rtf.pdf

一部抜粋

> 2.ADDITIONAL LICENSING REQUIREMENTS AND/OR USE RIGHTS.
>  a.Distributable Code. The software contains code that you are permitted to distribute in programs you develop if you comply with the terms below.
>   i.Right to Use and Distribute. The code and test files listed below are “Distributable Code”.
>    • REDIST.TXT Files. You may copy and distribute the object code form of code listed in REDIST.TXT files plus the files listed on the REDIST.TXT list located at [http://go.microsoft.com/fwlink/?LinkId=524842](). Depending on the specific edition of the software, the number of REDIST files you receive with the software may not be equal to the number of REDIST files listed in the REDIST.TXT List. We may add additional files to the list from time to time.
>    • Third Party Distribution. You may permit distributors of your programs to copy and distribute the Distributable Code as part of those programs. 
>   ii. Distribution Requirements. For any Distributable Code you distribute, you must
>    •  Add significant primary functionality to it in your programs;
>    • `For any Distributable Code having a filename extension of .lib, distribute only the results of running such Distributable Code through a linker with your program;`
>    • Distribute Distributable Code included in a setup program only as part of that setup program without modification;
>    • Require distributors and external end users to agree to terms that protect it at least as much as this agreement;
>    • For Distributable Code from the Windows Performance Toolkit portions of the software, distribute the unmodified software package as a whole with your programs, with the exception of the KernelTraceControl.dll and the WindowsPerformanceRecorderControl.dll which can be distributed with your programs;
>    • Display your valid copyright notice on your programs; and
>    • Indemnify, defend, and hold harmless Microsoft from any claims, including attorneys’ fees, related to the distribution or use of your programs. 
>   iii. Distribution Restrictions. You may not
>    • Alter any copyright, trademark or patent notice in the Distributable Code;
>    • Use Microsoft’s trademarks in your programs’ names or in a way that suggests your programs come from or are endorsed by Microsoft;
>    • Distribute partial copies of the Windows Performance Toolkit portion of the software package with the exception of the KernelTraceControl.dll and the WindowsPerformanceRecorderControl.dll which can be distributed with your programs;
>    • Distribute Distributable Code to run on a platform other than the Microsoft operating system platform;
>    • Include Distributable Code in malicious, deceptive or unlawful programs; or
>    • Modified or distribute the source code of any Distributable Code so that any part of it becomes subject to an Excluded License. And Excluded License is one that requires, as a condition of use, modification or distribution, that
>    • The code be disclosed or distributed in source code form; or
>    • Others have the right to modify it.


7. SCOPE OF LICENSE. The software is licensed, not sold. This agreement only gives you some rights to use the software. Microsoft reserves all other rights. Unless applicable law gives you more rights despite this limitation, you may use the software only as expressly permitted in this agreement. In doing so, you must comply with any technical limitations in the software that only allow you to use it in certain ways. You may not

>  • Except for the Microsoft .NET Framework, disclose to a third party the results of any benchmark test of the software, without first obtaining Microsoft's prior written approval;  
>  • work around any technical limitations in the software;  
>  • reverse engineer, decompile or disassemble the software, except and only to the extent that applicable law expressly permits, despite this limitation;  
>  • make more copies of the software than specified in this agreement or allowed by applicable law, despite this limitation;  
>  • publish the software for others to copy;  
>  • rent, lease or lend the software;  
>  • transfer the software or this agreement to any third party; or  
>  • use the software for commercial software hosting services.

要約すると「あなたの作成した主要な機能を含むプログラムからしか使えないように、リンカーで結合して、アプリケーション一式をセットアップパッケージにまとめて,Microsoftの著作権を表示させ、このライセンスと同等以上のライセンスをエンドユーザーに求めること。dllやpydにして、これだけを抜き出して使わせるな、それはライセンス回避だからダメ」

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VisualStudioには、%ProgramFiles%\Microsoft Visual Studio\2022\Enterprise\Licensesのような場所に同様のrtfがあります。(上記SDKとほぼ同文)

VCのlibはVisualStudio付属であり、VisualStudioのライセンスをもたない人はビルドできないから、dllやpydにリンクさせてあなたのアプリケーション以外から使えるようにしたら駄目でしょう。

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# 最近pythonのライブラリにVCのDLLを含めて配布したいというAIらしき質問が大量に投稿されている…

Answer 2

Visual Studio Community をライセンス条項に則って使用している限り、Visual C++ ランタイムは再配布可能です。

• サポートされている最新の Visual C++ 再頒布可能パッケージのダウンロード | Microsoft Learn
• Visual C++ ファイルの再配布 | Microsoft Learn