[BUG] Claude Code Chat isn't working

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code process exited with code 3. stderr: ============================================================
Bun v1.4.0 (8bb8d04c4) Windows x64
Windows v10.26200
CPU: sse42 avx avx2
Args: "<home>\AppData\Roaming\Claude\claude-code\2.1.229\claude.exe" "--output-format" "stream-json" "--verbose" "--input-format" "stream-json" "--effort" "high" "--model" "claude-opus-5" "--permission-prompt-tool" "stdio" "--allow"...
Features: jsc standalone_executable claude_code
Builtins: "bun:main"

Elapsed: 248ms | User: 140ms | Sys: 93ms
RSS: 0.16 GB | Peak: 0.16 GB | Commit: 132.73 MB | Faults: 39747 | Machine: 12.62 GB

panic(main thread): Segmentation fault at address 0xFFFFFFFFFFFFFFFF
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

To send a redacted crash report to Bun's team,
please file a GitHub issue using the link below:

https://bun.report/1.4.0/w_18bb8d04kggggIggggCykpigC6lrmgC0/<blob>//npB2+58V49u8VmrqkWqrmjOA2DD

============================================================
Bun v1.4.0 (8bb8d04c4) Windows x64
Windows v10.26200
CPU: sse42 avx avx2
Args: "<home>\AppData\Roaming\Claude\claude-code\2.1.229\claude.exe" "--output-format" "stream-json" "--verbose" "--input-format" "stream-json" "--effort" "high" "--model" "claude-opus-5" "--permission-prompt-tool" "stdio" "--allow"...
Features: jsc standalone_executable claude_code
Builtins: "bun:main"
Elapsed: 248ms | User: 140ms | Sys: 93ms
RSS: 0.16 GB | Peak: 0.16 GB | Commit: 132.73 MB | Faults: 39747 | Machine: 12.62 GB
panic(main thread): Segmentation fault at address 0xFFFFFFFFFFFFFFFF
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
To send a redacted crash report to Bun's team,
please file a GitHub issue using the link below:
https://bun.report/1.4.0/w_18bb8d04kggggIggggCykpigC6lrmgC0/<blob>//npB2+58V49u8VmrqkWqrmjOA2DD

What Should Happen?

Claude Code should launch normally and let me send messages in the chat. Instead, the process crashes on startup — it exits with code 3 due to a segmentation fault in the bundled Bun runtime, before I can chat at all.

Error Messages/Logs

Claude Code process exited with code 3. stderr:
============================================================
Bun v1.4.0 (8bb8d04c4) Windows x64
Windows v10.26200
CPU: sse42 avx avx2
Args: "<home>\AppData\Roaming\Claude\claude-code\2.1.229\claude.exe" "--output-format" "stream-json" "--verbose" "--input-format" "stream-json" "--effort" "high" "--model" "claude-opus-5" "--permission-prompt-tool" "stdio" "--allow"...
Features: jsc standalone_executable claude_code
Builtins: "bun:main"
Elapsed: 458ms | User: 62ms | Sys: 109ms
RSS: 0.16 GB | Peak: 0.16 GB | Commit: 132.67 MB | Faults: 39719 | Machine: 12.62 GB
panic(main thread): Segmentation fault at address 0xFFFFFFFFFFFFFFFF
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
To send a redacted crash report to Bun's team,
please file a GitHub issue using the link below:
https://bun.report/1.4.0/w_18bb8d04kggggIggggCykpigC6lrmgC0/<blob>//npB2+58V49u8VmrqkWqrmjOA2DD

Steps to Reproduce

1. Open the Claude Code desktop app on Windows 10 (build 26200)
2. Open or start a chat session ("Is this working?")
3. Send a message / try to interact with Claude Code
4. The Claude Code process immediately crashes — process exits with code 3
5. stderr shows Bun v1.4.0 panicking with a segmentation fault at startup

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.229

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

• This crash happens immediately on startup/first interaction — the process never gets far enough to actually chat.
• Bun's own crash reporter generated a report link, which may be useful to cross-reference:

https://bun.report/1.4.0/w_18bb8d04kggggIggggCykpigC6lrmgC0/<blob>//npB2+58V49u8VmrqkWqrmjOA2DD

• The in-app "Submit feedback / bug report" dialog inside Claude Code also failed to send ("Couldn't send feedback. Try again."), which is why I'm filing this directly on GitHub instead.
• Machine specs from the crash log: RSS 0.16 GB, Peak 0.16 GB, Commit 132.67 MB, 12.62 GB total machine memory — doesn't look like a resource-exhaustion issue.
• Possible duplicate: issue #62055 ("[BUG] Claude Code process exited with code 3") looks related — may be the same underlying bug.