Markdown files not appearing in JetBrains Rider search results for Unity projects

Problem

When working on a Unity project in JetBrains Rider, Markdown (.md) files within the project are not found via "Search Everywhere" (double-shift) or "Find in Files."

While these files may appear briefly during the initial indexing phase, they disappear from search results once indexing is complete. The files only become searchable again after they have been manually opened in the editor.

Cause

In Unity-based projects, Rider relies on the project metadata generated by Unity. By default, Unity's project generation settings may not include the .md extension in the generated .csproj files. If a file extension is not included in the project structure recognized by the IDE, Rider may exclude those files from the global index once the initial background scan synchronizes with the project's official file list.

Resolution

To resolve this, you must ensure that Unity includes Markdown files when generating the project files for Rider.

1. Open your project in the Unity Editor
2. Navigate to Edit → Project Settings
3. In the sidebar, select Editor
4. Locate the section C# Project Generation
5. Find the field labeled Additional extensions to include
6. Add md to the list of extensions (ensure extensions are separated by a semicolon)
7. Next, navigate to Unity → Preferences (on macOS) or Edit → Preferences (on Windows)
8. Go to External Tools
9. Click the Regenerate project files button
10. Close Rider and reopen the project to allow it to re-index the newly included files