Trace trap (SIGTRAP / EXC_BREAKPOINT) on startup — Claude Code 2.1.1 on macOS 26.3 (arm64)

Found 3 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/15925
2. https://github.com/anthropics/claude-code/issues/9722
3. https://github.com/anthropics/claude-code/issues/11201

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🤖 Generated with Claude Code

Additional details after disabling all plugins:

• claude --version → 2.1.1 (Claude Code)
• claude --help works
• claude → zsh: trace trap claude

Crash report summary (~/Library/Logs/DiagnosticReports/2.1.1-2026-01-08-190814.ips):

• exception: EXC_BREAKPOINT / SIGTRAP
• termination: Trace/BPT trap: 5
• faultingThread: 12
• triggered thread: Bun Pool 3
• ESR: (Breakpoint) pointer authentication trap IB

Debug log excerpt (~/.claude/debug/ac380475-6f09-47bf-91f1-5a4d7451c7dd.txt):

2026-01-09T00:16:57.390Z [DEBUG] Found 6 plugins (0 enabled, 6 disabled)
2026-01-09T00:16:57.494Z [DEBUG] Plugin loading errors: Plugin content-tools not found in marketplace redi-claude-skills, Plugin ralph-wiggum not found in marketplace claude-plugins-official
2026-01-09T00:16:57.494Z [DEBUG] getPluginSkills: Processing 0 enabled plugins
2026-01-09T00:16:57.499Z [DEBUG] [STARTUP] Running showSetupScreens()...
2026-01-09T00:16:58.121Z [DEBUG] [STARTUP] showSetupScreens() completed in 622ms
2026-01-09T00:16:58.122Z [DEBUG] [API:auth] OAuth token check starting
2026-01-09T00:16:58.172Z [DEBUG] [API:auth] OAuth token check complete

Full crash report and debug log available if needed.

Following, seems to happen more in iterm2 than terminal

For me the problem were massive session files. after removing them, issue is gone

<img width="975" height="105" alt="Image" src="https://github.com/user-attachments/assets/e949e3e9-70e4-42ab-89af-54b8b31d8c36" />

<img width="914" height="297" alt="Image" src="https://github.com/user-attachments/assets/1295cfdd-6743-4817-acbb-58960142078a" />

Hypothesis based on this page:

1. multi‑GB session logs are scanned at startup
2. the process attempts to load them
3. which leads to memory corruption in a Bun pool thread
4. and an ARM64 PAC validation failure
5. resulting in SIGTRAP

This is inferred from the discussion about large session files and my local ips crash report.

It worked for me to delete large session files 👍 - this should be some sort of automated process.

delete the json files also did it for me, renaming the projects folder also does the trick in you home and then .claude

Just got the same bug, deleting a massive 2.91 GB jsonL file worked. No idea how a single session got so large.

Possibly linked to https://github.com/oven-sh/bun/issues/26323

Confirmed:

% du -h -c -d1 .
103M	./e759a176-fda4-4e6c-bf88-80fb6762b21c
2.3G	.
2.3G	total
% ll
total 4702720
-rw-------  1 schittenden  staff        5159 Jan 16 11:40 99b2f42b-e0f1-49ee-b03b-cfb93327171e.jsonl
-rw-------  1 schittenden  staff       19393 Jan 20 06:16 b666b120-5569-4a93-a8e4-9186474830f5.jsonl
drwx------  4 schittenden  staff         128 Jan 16 12:00 e759a176-fda4-4e6c-bf88-80fb6762b21c
-rw-------  1 schittenden  staff  2407755863 Jan 20 13:32 e759a176-fda4-4e6c-bf88-80fb6762b21c.jsonl
-rw-------  1 schittenden  staff        1465 Jan 16 11:43 sessions-index.json
% rm e759a176-fda4-4e6c-bf88-80fb6762b21c.jsonl

Stupidly, I should have made a backup of this file first for investigation. But, I can confirm that cd $HOME/.claude/projects/$MY_PROJECT_PATH + rm "fixed" the claude startup problem.

macOS 15.0 Sequoia (24A335)
Mac Air M2 (darwin-arm64)
claude-hfi 2.1.31
Erro: malloc: pointer being freed was not allocated + trace trap