Claude Desktop crashes on macOS Tahoe 26.3.1 — Crashpad mach_port_request_notification failure
Status Fixed / completed
Maintainer reply None cached
Workaround ✓ Mentioned in description ↑
Activity 5 comments · opened Mar 21, 2026 · closed Mar 28, 2026
Summary
Claude Desktop (v1.1.7714) crashes repeatedly on macOS Tahoe 26.3.1. Started the week of March 12, 2026. Same hardware/OS configuration works fine on a second machine.
Environment
- macOS: Tahoe 26.3.1, Build 25D771280a
- Hardware: Apple M4 Pro, 24GB RAM (Mac16,7)
- Claude Desktop: v1.1.7714, Electron 40.4.1
- Installed via: Homebrew Cask
Root Cause
Crashpad (chrome_crashpad_handler) fails on mach_port_request_notification with KERN_INVALID_CAPABILITY (error 20). This error fires every ~1 second and eventually kills the main Electron process.
Exact error (repeats every second):
[FATAL:third_party/crashpad/crashpad/handler/mac/exception_handler_server.cc:76]
Check failed: kr == KERN_SUCCESS. mach_port_request_notification: (os/kern) invalid capability (20)Crash report exception:
"exception": {
"codes": "0x0000000000000001, 0x00000001004e7380",
"type": "EXC_BREAKPOINT",
"signal": "SIGTRAP"
}Behavior
- App launches, shows login screen briefly, then crashes (15-30 seconds)
- Crashes whether logged in or not
- When crashpad binary is physically removed, app survives much longer (2+ minutes, completed login and Co-Work session), confirming crashpad as the cause
- However, modifying the binary breaks code signature → "invalid installation" error, so this is not a viable user workaround
What Was Tried (all failed to resolve)
- Full uninstall/reinstall via
brew reinstall --cask claude(multiple times) - Complete deletion of
~/Library/Application Support/Claude/ - Deleting Cookies, Preferences, Keychain entries (
Claude Safe Storage) tccutil reset All com.anthropic.claudefordesktop- Removing quarantine:
xattr -cr /Applications/Claude.app - Launch flags:
--disable-gpu,--disable-crash-reporter,--password-store=basic,--disable-breakpad - Environment variables:
ELECTRON_DISABLE_CRASH_REPORTER=1
Suggested Fix
Update Crashpad to handle KERN_INVALID_CAPABILITY gracefully on macOS Tahoe, or add error recovery so the FATAL assertion doesn't propagate to the main process.
Diagnostic Evidence
- 79 crash reports in
~/Library/Logs/DiagnosticReports/chrome_crashpad_handler-*.ips - Full stderr capture showing the FATAL loop available on request
5 Comments
Update: Still reproducible on v1.1.8308
Upgraded to v1.1.8308 today (2026-03-23) — same crash, same error, still unfixed.
This repeats every ~1 second and eventually kills the main process. Full fresh install (deleted app + all app data, reinstalled via brew), same result.
Also flagging: this issue was labeled
invalidbut it is a reproducible, hardware-confirmed crash. Themach_port_request_notificationFATAL in Crashpad's exception handler server is the direct cause — not a misconfiguration or user error. Would appreciate a re-triage.Wanted to add some urgency here — I'm on the Max plan ($200/month) and Claude Desktop has been completely unusable for 11 days now (since ~March 12). Co-Work and Dispatch are desktop/iOS only features, so I'm locked out of core functionality I'm paying for.
This issue was auto-labeled
invalidbut the crash is 100% reproducible, survives full reinstalls, and still occurs on v1.1.8308 (latest). Would really appreciate a human review and a status update on whether a fix is in progress.Requesting re-triage:
invalidlabel is incorrectThis issue was auto-labeled
invalidbut is a reproducible crash with a clear stack trace. Requesting label change tobug.Evidence attached
1. macOS Crash Report (
Claude-2026-03-21-155639.ips)EXC_BREAKPOINT/SIGTRAPin Crashpad'smach_port_request_notificationCoreFoundation: *** multi-threaded process forked ***libsystem_c.dylib: crashed on child side of fork pre-exec2. System Info
3. Reproduction
Root cause hypothesis
The
"crashed on child side of fork pre-exec"ASI annotation combined with the Crashpadmach_port_request_notificationfailure suggests Electron's Crashpad handler is forking a child process that inherits mach port state incompatible with macOS Tahoe 26.3.1's kernel. This is a known class of Chromium issues on newer macOS versions.Impact
Max plan subscriber ($200/mo) — Claude Desktop completely unusable since ~March 12. Co-Work and Dispatch features are desktop-only, so this blocks core paid functionality.
Cross-referencing duplicate reports
This issue is not isolated — multiple users are reporting the same Crashpad
mach_port_request_notificationcrash across macOS Tahoe versions:All share the same root cause: Crashpad's
exception_handler_server.cc:76fails withKERN_INVALID_CAPABILITY (20)on macOS 26's updated Mach port APIs. The FATAL assertion fires every ~1 second and eventually kills the Electron process.This issue has been open 14 days with no Anthropic response and is incorrectly labeled
invalid. Requesting re-triage tobug.This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.