How I Fixed the ‘Cannot Activate PlatformIO IDE’ Error in Cursor After Installing the C/C++ Extension

I recently switched to Cursor IDE for my C++ development work, excited about its AI features, but I quickly ran into a roadblock. After installing the ‘C/C++’ extension from Anysphere, I kept seeing an error that ‘PlatformIO IDE’ wouldn’t activate, with a message like: ‘Cannot activate the ‘PlatformIO IDE’ extension because it depends on the ‘C/C++’ extension from ‘Anysphere’, which is not installed.’ This halted my progress on embedded projects, and I needed a fix fast.

The Core Problem I Faced

The issue stems from a dependency conflict. PlatformIO IDE relies on the ‘C/C++’ extension from Microsoft (ms-vscode.cpptools), which isn’t compatible with Cursor. Even after reinstalling everything or trying the forked version, I got stuck with activation errors or annoying popups asking to remove incompatible extensions. On both Windows and Linux systems, this broke my workflow completely.

My Step-by-Step Workaround That Worked

Through trial and error, I discovered a manual patching method that resolved the issue without waiting for an official update. Here’s exactly what I did:

• First, locate the PlatformIO IDE extension folder. On Windows, it’s typically at %USERPROFILE%\.cursor\extensions\platformio.platformio-ide-[version]\. On Linux, it’s something like /home/yourusername/.cursor/extensions/platformio.platformio-ide-[version]/. Replace [version] with your installed version number.
• Next, open the package.json file in a text editor. Find the line that says "extensionDependencies": ["ms-vscode.cpptools"] and change it to "extensionPack": ["ms-vscode.cpptools"]. This tweak prevents the dependency check from failing.
• Then, open the .vsixmanifest file in the same folder. Remove the line: <Property Id="Microsoft.VisualStudio.Code.ExtensionDependencies" Value="ms-vscode.cpptools" />. This stops Cursor from forcing uninstallation prompts.
• After saving both files, uninstall the ‘ms-vscode.cpptools’ extension if it’s still installed, then restart Cursor. This should activate PlatformIO IDE without errors.

For example, after making these changes on my Windows machine, I no longer saw the activation popup, and I could get back to coding. On Linux, the process was similar and just as effective.

What About Intellisense Issues?

After applying this fix, I noticed that intellisense wasn’t working perfectly for some users. In my case, it improved, but if it persists, I recommend checking for extension updates or reinstalling PlatformIO IDE after the patch. The developers have hinted at a permanent fix in an upcoming Cursor update, so this workaround is a solid temporary solution.

Key Takeaways for Smooth Development

This experience taught me to always verify extension dependencies in niche IDEs like Cursor. While this manual edit might feel hacky, it saved my project deadlines. Keep an eye out for official patches from Anysphere, as they’re actively addressing this. For now, this workaround lets you leverage PlatformIO IDE fully in Cursor, keeping your AI-powered coding journey on track.