The BC2001 error documentation was minimal and didn't address key user concerns about where files are referenced and why the compiler is looking for missing files. Users reported confusion about:

• Why the compiler is looking for the missing file at all
• Where the file is referenced in their project
• What "vbc" means in the File column of error messages
• How to identify the source when files are intentionally excluded

This update significantly expands the documentation to provide:

Enhanced error context: Explains that the error occurs when the Visual Basic compiler (vbc) cannot find a referenced file, clarifying why "vbc" appears in the File column.

Common causes section: Details the four main ways files can be referenced:

• Command-line compilation arguments
• Response files (.rsp files)
• Project references to assemblies/modules
• Compiler options like -reference, -addmodule, -keyfile

Comprehensive troubleshooting: Expands the single "check the path" instruction into five specific, actionable steps covering file paths, response files, project references, compiler options, and intentionally excluded files.

Additional resources: Adds links to relevant compiler documentation for response files and reference options, plus Visual Studio project management guidance.

The documentation now directly addresses the scenario mentioned in the issue where files are "excluded from the project intentionally" but still referenced elsewhere, providing clear guidance on how to resolve such conflicts.

Fixes #33861.

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

Internal previews