[Bug] Doesnt' start

[elidub]

Category

Check all that apply:

• Keystroke / Input (Tab not working, keystrokes swallowed, input blocked)
• App Compatibility (bug only in a specific app: Word, Outlook, Mail, browser, etc.)
• Performance / Crash (slow response, hang, or crash)

Summary

When I try to start/open CoTabby, the app doesn't open.

Environment

• macOS version: 15.0. MacBook Air M2 16GB
• Host app: N/A
• Cotabby engine: N/A
• Model name (if Open Source): N/A
• Accessibility permission granted: yes
• Input Monitoring permission granted: no (CoTabby doesn't appear here in the settings)
• Screen Recording permission granted: no (CoTabby doesn't appear here in the settings)

Steps to reproduce

1. Download CoTabby (tried both via website and brew)
2. Install CoTabby
3. Try to start CoTabby

Expected behavior

CoTabby starts and something opens

Actual behavior

Nothing happens

[FuJacob]

@elidub please give access to the other settings. if it does not appear you will need to click the press + button in the settings and add it manually by searching for cotabby.

after you do this, please try opening again. then check the taskbar for the cotabby logo. let me know if you still have issues

[elidub]

@FuJacob Thanks for the reply, don't know how I didn't think of that. 😳 However, still the same issue. What I did:

1. Manually add Input Monitoring and Screen Recording with the + button and turn them on.
2. Turn all 3 permission settings (Accessibility, Input Monitoring and Screen Recording) off and on.
3. Restart my Mac.
4. Repeat step 2.

After each step, I've tried to start CoTabby, but still nothing happens or appears.

[elidub]

@FuJacob I don't have any app development experience, so I'm sorry for any un unhelpful comments.

Did some chatting with Claude and it thinks it's because I'm on macOS 15. I'm not sure but, that might point you in the right direction:

Claude's response

Did some more digging — this turns out not to be a permissions or Gatekeeper issue. The app is crashing on launch with SIGABRT, before any UI ever appears.

Environment

• MacBook Air M2, 16 GB
• macOS 15.0 (stock, first Sequoia build)
• Installed via Homebrew (also tried the website .dmg), same result

Ruled out: Gatekeeper / notarization

$ spctl -a -vv /Applications/Cotabby.app
/Applications/Cotabby.app: accepted
source=Notarized Developer ID
origin=Developer ID Application: Jacob Fu (G946M8K23B)

Notarization is fine, so macOS isn't blocking it.

What actually happens

Running the binary directly aborts immediately:

$ /Applications/Cotabby.app/Contents/MacOS/Cotabby
zsh: abort      /Applications/Cotabby.app/Contents/MacOS/Cotabby

pgrep -lf cotabby returns nothing — the process never survives startup. That also explains the permissions state in my original report: Accessibility gets requested, but the app dies before it ever reaches the point of requesting Input Monitoring / Screen Recording, so those two never show up in System Settings.

Crash report (trimmed)

EXC_CRASH (SIGABRT) → abort() called, crashed thread 0 (com.apple.main-thread):

AttributeGraph   AG::precondition_failure(...)
AttributeGraph   create_offset_attribute(...)
SwiftUICore      _GraphValue.subscript.getter
SwiftUI          ModifiedContent<>._makeScene(scene:inputs:)
SwiftUI          _SceneModifier<>._makeScene(modifier:inputs:body:)
SwiftUI          AppGraph.instantiateOutputs()
SwiftUI          GraphHost.instantiate()
SwiftUI          runApp<A>(_:)
SwiftUI          App.main()
dyld             start

Diagnosis

This is a SwiftUI AttributeGraph precondition failure while instantiating the Scene graph — it aborts inside App.main() before any view or engine code runs. The _SceneModifier._makeScene frame means the trigger is a modifier applied to a Scene in the App body (e.g. MenuBarExtra style, Settings, .commands, .defaultSize, .windowResizability), not view content.

My best guess is an availability mismatch: the build targets a newer SDK (macOS 26, presumably for the Apple Intelligence path) while the deployment floor is 15.0, and a scene modifier that isn't valid on 15.0 is being applied unconditionally. Looks like 15.0 may not have been tested even though it's listed as the minimum.

Workaround

For anyone else hitting this on an early Sequoia build: updating macOS avoids it. I'll confirm which version resolves it once I've updated.

Possible fix

Gate the newer scene modifier behind if #available(macOS 26, *) { … } else { … }, or raise the actual deployment target to match what's supported.

Happy to share the full .ips crash report if it's useful.

[FuJacob]

Thank you for this, super helpful. Will take a look soon!!

[elidub]

I upgraded to Tahoe 26.5.2 and now CoTabby works!