What this error means
File has not been read yet (case-sensitive path mismatch on Windows) is a Claude Code failure pattern reported for developers trying to fix claude code file has not been read yet error caused by case-sensitive path comparison on windows. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.
Why this happens
Harness internal 'this file has been read' tracker uses case-sensitive string comparison on file paths. Windows filesystems are case-insensitive, so two paths resolving to the same file are treated as different. Causes repeated edit failures.
Common causes
- On Windows, Claude Code's internal file tracker uses case-sensitive string comparison. Paths like c:\Users\...\foo.md and C:\Users\...\foo.md are treated as different files, causing spurious 'File has not been read yet' errors that block edits.
- Harness internal 'this file has been read' tracker uses case-sensitive string comparison on file paths. Windows filesystems are case-insensitive, so two paths resolving to the same file are treated as different. Causes repeated edit failures.
Quick fixes
- Confirm the exact error signature matches
File has not been read yet (case-sensitive path mismatch on Windows). - Check the Claude Code account, local tool state, and provider configuration involved in the failing workflow.
- Compare the failing environment with a known working setup, then change one configuration value at a time.
Platform/tool-specific checks
- Verify the command, editor, extension, or API client that produced the error.
- Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
- Avoid deleting credentials, local model data, or project settings until the failing scope is clear.
Step-by-step troubleshooting
- Capture the exact error message and the command, editor action, or request that triggered it.
- Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
- Review the source evidence below and compare it with your environment.
- Apply one change at a time and rerun the smallest failing action.
- Keep the working fix documented for the team or deployment environment.
How to prevent it
- Keep provider/tool configuration documented.
- Record non-secret diagnostics such as tool version, provider name, model name, and command path.
- Add a lightweight check before CI or production workflows depend on the tool.