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

  1. Confirm the exact error signature matches File has not been read yet (case-sensitive path mismatch on Windows).
  2. Check the Claude Code account, local tool state, and provider configuration involved in the failing workflow.
  3. 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

  1. Capture the exact error message and the command, editor action, or request that triggered it.
  2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
  3. Review the source evidence below and compare it with your environment.
  4. Apply one change at a time and rerun the smallest failing action.
  5. 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.