claude-code - 💡(How to fix) Fix EBUSY: concurrent instances race on .claude.json (Windows) [1 comments, 2 participants]

ERROR EBUSY: resource busy or locked, open 'C:\Users<user>.claude.json'

TL;DR

Implementing a write-to-temp-then-rename pattern or proper file locking can resolve the EBUSY: resource busy or locked errors when writing to ~/.claude.json.

Guidance

• Consider using a temporary file for writing and then renaming it to ~/.claude.json to avoid concurrent access issues.
• Implement proper file locking mechanisms to prevent multiple processes from accessing the file simultaneously.
• Review the writeFileSync function calls to ensure they are properly synchronized across multiple instances of Claude Code.
• Evaluate the feasibility of using a more robust storage solution that supports concurrent access, such as a database.

Example

const temp = require('temp');
const fs = require('fs');

// Create a temporary file
const tmpFile = temp.path({ suffix: '.json' });

// Write to the temporary file
fs.writeFileSync(tmpFile, jsonData);

// Rename the temporary file to the target file
fs.renameSync(tmpFile, '~/.claude.json');

Notes

The provided solution assumes that the writeFileSync function is the primary cause of the issue. However, other factors, such as the underlying file system or operating system configuration, may also contribute to the problem.

Recommendation

Apply a workaround by implementing a write-to-temp-then-rename pattern, as this approach can be implemented without modifying the underlying file locking mechanisms.