Segmentation fault crash on Windows 11 in VS Code extension v2.0.29+ (Bun v1.3.1 runtime crash)

Environment:

• OS: Windows 11 Enterprise (Build 26100 / x64)
• VS Code Version: 1.105.1
• Claude Code Extension Versions Affected: v2.0.29 through v2.0.35 (latest)
• Last Working Version: v2.0.28
• Shell: Git Bash (C:\AppInstall\scoop\apps\git\current\bin\bash.exe)

Description:
The Claude Code VS Code extension crashes immediately upon opening the extension window to start a new conversation. The crash is 100% reproducible and occurs in all versions after v2.0.28.

Error Message:

panic(main thread): Segmentation fault at address 0x113
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Exit Code: 3 (SIGQUIT/Abort)

Bun Version: v1.3.1 (89fa0f34) bundled with extension

Full Stack Trace:

2025-11-07 12:06:52.563 [info] From claude: ============================================================
Bun v1.3.1 (89fa0f34) Windows x64 (baseline)
Windows v.win11_dt
CPU: sse42 avx avx2
Args: "c:\AppInstall\scoop\apps\vscode\1.105.1\data\extensions\anthropic.claude-code-2.0.35-win32-x64\resources\native-binary\claude.exe" "--output-format" "stream-json" "--verbose" "--input-format" "stream-json" "--append-system-prompt"...
Features: Bun.stderr(2) Bun.stdin(2) Bun.stdout(2) fetch(6) jsc spawn(11) standalone_executable 

Elapsed: 2288ms | User: 750ms | Sys: 796ms
RSS: 0.47GB | Peak: 0.47GB | Commit: 0.46GB | Faults: 123306 | Machine: 33.91GB

panic(main thread): Segmentation fault at address 0x113
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/1.3.1/e_189fa0f3Az/7v//BCWctiuser.dllg4ngBCWctiuser.dllog9fCYKERNEL32.DLLsu+JCcKERNELBASE.dllov+lBCcKERNELBASE.dllsuglBCYKERNEL32.DLLotjPCWctiuser.dllu/ueow8q0BunxoDm5slkB2/y9jB__0s521CA2AmR

panic: Segmentation fault at address 0x113
panicked during a panic. Aborting.

Claude Code process exited with code 3

When It Crashes:
Based on VS Code Output logs, the crash occurs during:

1. Shell snapshot creation (\[DEBUG] Creating shell snapshot for bash\)
2. Configuration file writes (atomic write operations to \.claude.json\)
3. Initialization phase before first user interaction

Relevant Log Excerpts:

[DEBUG] Creating shell snapshot for bash (C:\AppInstall\scoop\apps\git\current\bin\bash.exe)
[DEBUG] Looking for shell config file: C:\Users\mark.campbell3\.bashrc
[DEBUG] Shell config file not found: C:\Users\mark.campbell3\.bashrc, creating snapshot with Claude Code defaults only
[DEBUG] Snapshots directory: C:\Users\mark.campbell3\.claude\shell-snapshots

Steps to Reproduce:

1. Install Claude Code VS Code extension v2.0.29 or later on Windows 11
2. Open VS Code
3. Click the Claude Code extension icon to open the chat panel
4. Extension crashes immediately with segmentation fault

Workaround:
Manually install v2.0.28 which works perfectly:

1. Download v2.0.28 VSIX from VS Code marketplace
2. Install using "Install from VSIX" in VS Code
3. Disable auto-updates for the extension

Attempts to Resolve:

• ✅ Uninstalled potentially conflicting extensions (GitHub Copilot)
• ✅ Verified file permissions on \C:\Users\mark.campbell3\.claude.json\
• ✅ Checked for antivirus interference
• ✅ Tested across multiple versions (v2.0.29 through v2.0.35) - all fail
• ✅ Confirmed v2.0.28 works reliably

Analysis:
This appears to be a Bun runtime regression introduced in v2.0.29. The segfault at address \0x113\ is a low-level memory access violation occurring during the initialization phase, specifically around shell snapshot creation and file I/O operations on Windows.

Impact:
The extension is completely unusable for Windows 11 users on all versions after v2.0.28.

Additional Context:

• No custom MCP servers configured
• No plugins enabled
• Standard Windows 11 Enterprise installation
• Git for Windows installed via Scoop package manager