Microsoft suddenly issued a "ban order"! Cursor is completely banned from using C, C++, and C# extensions, and developers are forced to roll back versions

In a VSCode language service extension from Microsoft, located atnativeStrings.jsonA line of code at line 485 of the file breaks compatibility with Cursor.

The terms state: "The C/C++ extension may only be used with Microsoft Visual Studio, Visual Studio for Mac, Visual Studio Code, Azure DevOps, Team Foundation Server, and subsequent Microsoft products and services to develop and test your applications." These restrictions make developers more inclined to use Microsoft's official distribution rather than other versions.

"license_terms": "The C/C++ extension may be used only with Microsoft Visual Studio, Visual Studio for Mac, Visual Studio Code, Azure DevOps, Team Foundation Server, and successor Microsoft products and services to develop and test your applications."

Later, some developers complained that some of Microsoft's closed-source extensions (Remote Access, Pylance, C/C++, C#) could no longer be used in Cursor or other non-Microsoft editors. Among them, Cursor 1.17.62 can be used normally, but 1.18.21 and higher versions cannot work properly.

Cursor's documentation provides instructions on how to install extensions from the Microsoft Store. This functionality relies on downloading the extension as.vsixfile; however, the download link for the file is no longer displayed on the extension market's homepage. In many cases, if the extension is open source, the developer can still download it from its code repository (such as GitHub).

In addition, some developers said that C# Dev Kit also encountered the same limitations.

Errors reported by Cursor when trying to use Microsoft's Dev Kit extensions

In response, Alexander Schroeder, a developer in the Cursor community, said, "We have released an immediate fix and will release a long-term solution soon."

Visual Studio Code released by Microsoft has completely changed the way developers use IDE. Developers can use a unified tool to write code in almost all languages ​​and technology stacks.

Microsoft not only provides Visual Studio Code, but also developed many extensions, such as Python debugger, C/C++ language service, Jupyter, Pylance, Python language service, Azure tools, Data Wrangler, Jupyter shortcut key mapping, and even JavaScript and TypeScript language services. These are just some of the many extensions developed by Microsoft. In addition, Microsoft also owns GitHub and npm, which can be said to control the entire software development tool ecosystem.

That would have been great, but things have been a little shaky for some teams at Microsoft lately — four MIT undergraduates took advantage of VSCode’s open source model, forked it, and built a competing product called Cursor. While VSCode asks if you want to merge AI suggestions into the code you’re developing, Cursor does the opposite, asking the AI ​​if it wants humans to get involved.

Cursor itself is not open source, which is controversial, but is allowed under the MIT license used by VSCode, so we cannot view its internal implementation or know what it does specifically.

However, Cursor raised about $60 million in funding in the middle of last year, and at about the same time, they already had about 40,000 users. Cursor offers a free policy with restrictions, and paid plans of $20 and $40 per month (billed by user).

Microsoft's C/C++ language service extension suddenly stopped supporting Cursor, which surprised everyone. However, this is not new. Some netizens said that Microsoft's own language extension has always stated that it cannot be used outside of Visual Studio Code (and Code forks do not count), and this is definitely not a new problem, but they have now decided to enforce restrictions on C++ extensions. In 2018, Microsoft made it clear that the C# extension was not allowed on Code forks.

The 192-line-long license file for Microsoft's vscode-cpp tool prohibits its use outside of VSCode and Microsoft tools.

Front-end engineer Tom Smykowski discovered that the new restriction was added on April 1, along with a comment from a reviewer:

“Embrace, extend, extinguish.”

This phrase isn't just a dig at the change, it actually comes from Microsoft itself:

"Embrace, Extend, Eliminate" (EEE), also known as "Embrace, Extend, Eradicate", is a strategic phrase used internally by Microsoft that the U.S. Department of Justice once discovered to describe its approach to entering certain product areas that adopt broad open standards: first "embrace" the standards, then "extend" them by adding proprietary features, and finally "eliminate" competitors through these differences.

This strategy was mentioned in many of Microsoft's antitrust cases in the last century, and it is being brought up again now, which shows that this move has caused considerable resentment in the developer community.

Specifically, the three stages of this strategy are as follows:

• Embrace : Develop software that is highly compatible with open standards.

• Extend : Add new functionality not supported by open standards, thus creating interoperability issues.

• Extinguish : When these extensions become de facto standards due to market share advantages, competitors that cannot support these extensions are marginalized.

Of course, Microsoft has never publicly admitted that this is their strategy. After all, VSCode is open source under the MIT license, and .NET is also open source, so it doesn't seem like Microsoft will implement an "EEE strategy".

However, in this case, Microsoft did take advantage of a license clause that has existed for many years and imposed restrictive blockades on extensions based on it . It didn't do this in the past, probably because no one took VSCode and tried to make a competing product.

So, how many extensions are affected by this limitation?

Smykowski said after investigating that he had not found any other extensions with similar blocking behavior . However, Smykowski had not checked all the content. A search on the entire web for phrases like "extension may be used only with" did not find more similar descriptions in Microsoft's open source code base.

The problem is that Microsoft can add such restrictions at any time . In fact, if you use an extension that contains the following statement:

“You may install and use any number of copies of Microsoft Visual Studio, Visual Studio for Mac, Visual Studio Code, Azure DevOps, Team Foundation Server, and their successor products and services solely for the development and testing of your applications.”

In theory, Microsoft may impose access restrictions on it in the future.

Obviously, this restriction enforces that the extension can only be used with Microsoft-specified tools and not with any forks .

When Smykowski looked for the phrase “only with Microsoft,” he didn’t find strong evidence that the licenses for other language service extensions included similar restrictions.

So Smykowski concluded that there is currently no similar blocking behavior among other language service extensions , and not all extensions use this restrictive license.

Smykowski recommends that developers should check the license of an extension before using it on a fork of VSCode, or choose to use other truly open source extensions with open licenses. "In fact, Microsoft's VSCode extension store is not the only source - for example, you can get extensions from Open VSX, which is hosted by the Eclipse Foundation."

The “lock-in effect” prompted the creation of the Open VSX Marketplace, which was originally intended to prevent the official VS Code-exclusive marketplace from “severely limiting the ability of organizations to adopt open source development tools.”

Despite this, the number and usage of extensions in the Open VSX Marketplace are still far lower than Microsoft's official marketplace. However, Cursor still provides access to VS Code Marketplace extensions in its IDE, including Microsoft's C/C++ extensions and C# DevKit, and also provides a settings option to import extensions from an installed VS Code.

It looks like Microsoft is now enforcing its terms of use more strictly. DevClass tried to install Microsoft's C/C++ extension in Cursor. Although the installation was successful, it did not work properly when using functions such as "Find All References". Finally, a prompt window popped up to remind the user that the extension has usage restrictions.

This is confusing because Cursor still recommends installing Microsoft's C++ extension when it identifies a suitable project. Developers may want to consider using alternatives such as the clangd extension, even though it has only been installed 1.7 million times, while Microsoft's extension has been installed 81 million times.

But the problem is: Although Microsoft provides extensions and VSCode for free, it does not mean that developers can use them for anything they want. They can change the license agreement at any time, restrict your use, or even require payment for use. "This means that the future is full of uncertainty, and when a company has control over a tool or platform, it also controls the rules ." Smykowski commented.

Regarding this change by Microsoft, some developers speculated that it might be due to the introduction of the AI ​​feature "Agent Mode" in the stable version of VS Code, making Cursor a more direct competitor of VS Code.

VS Code Stable introduced Agent mode in the March version, which now fully supports MCP.

Unlike traditional chat or multi-file editing functions, the core of the agent mode is that it not only answers questions, but also has the practical ability to convert developers' ideas into code : automatically identify or generate required files, complete all necessary subtasks, and ensure that the developer's main goals are achieved; recommend terminal commands or tool calls and request developers to execute them; have runtime error analysis and self-repair capabilities, etc.

The proxy mode is supported by Claude 3.5 and 3.7 Sonnet, Google Gemini 2.0 Flash, and OpenAI GPT-4o. Currently, the proxy mode has a pass rate of 56.0% in the SWE-bench Verified test based on Claude 3.7 Sonnet.

Microsoft has always emphasized that although the Code-OSS code is an open source project based on the MIT license agreement, VS Code is a distribution customized by Microsoft based on the Code-OSS repository and is released using the traditional Microsoft product license agreement.

Some comments pointed out that in terms of compliance, Cursor may not link directly to the VS Code extension market, but instead publish links to online extensions through its own service. The current problems seem to be limited to Microsoft's official extensions, not third-party extensions.

Reference Links:

https://github.com/microsoft/vscode-cpptools/blob/main/RuntimeLicenses/cpptools-LICENSE.txt

https://github.com/getcursor/cursor/issues/2976

https://tomaszs2.medium.com/microsoft-quietly-blocked-cursor-from-using-its-vscode-extension-heres-the-line-of-code-that-8d664caf0de5

https://devclass.com/2025/04/08/vs-code-extension-marketplace-wars-cursor-users-hit-roadblocks/

https://github.blog/news-insights/product-news/github-copilot-agent-mode-activated/

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