[BUG] Crash on startup: "sandbox required but unavailable" on macOS Tahoe 26.4

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 crashes immediately on startup with a sandbox-related error. The
process refuses to start because sandbox.failIfUnavailable is set but the
sandbox is reported as unavailable.

Environment:

• Claude Code version: 2.1.120
• OS: macOS 26.4 (Tahoe), build 25E246
• Architecture: arm64 (Apple Silicon)
• Kernel: Darwin 25.4.0
• Bun: 1.3.11

What Should Happen?

It should resume a session

Error Messages/Logs

9252: Error: sandbox required but unavailable: ${f_}
 9253 `+`  sandbox.failIfUnavailable is set \u2014 refusing to start without a
 :   working sandbox.
 9254:

 - <anonymous> (/$bunfs/root/src/entrypoints/cli.js:9251:5663)
 - WC (/$bunfs/root/src/entrypoints/cli.js:492:63749)
 - pj (/$bunfs/root/src/entrypoints/cli.js:492:76948)
 - fT (/$bunfs/root/src/entrypoints/cli.js:492:76827)
 - pj (/$bunfs/root/src/entrypoints/cli.js:492:77745)
 - fT (/$bunfs/root/src/entrypoints/cli.js:492:76827)
 - pj (/$bunfs/root/src/entrypoints/cli.js:492:76926)
 - fT (/$bunfs/root/src/entrypoints/cli.js:492:76827)
 - pj (/$bunfs/root/src/entrypoints/cli.js:492:77745)
 - fT (/$bunfs/root/src/entrypoints/cli.js:492:76827)
 - async <anonymous> (/$bunfs/root/src/entrypoints/cli.js:18815:2361)

Steps to Reproduce

Steps to reproduce:

1. Run claude in terminal
2. Crash occurs immediately before any interaction

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.118

Claude Code Version

2.1.120

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_