`-[NSCarbonMenuImpl _menuLostMainMenuStatus]` calls [`-[NSFastEnumeration countByEnumeratingWithState:objects:count:]`](https://developer.apple.com/documentation/foundation/nsfastenumeration/1412867-countbyenumeratingwithstate) on the `NSCarbonMenuImpl` object's array of menu items. I bet this is where the "mutation" error happens.
Bug 1765391 Comment 52 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
`-[NSCarbonMenuImpl _menuLostMainMenuStatus]` calls [`-[NSFastEnumeration countByEnumeratingWithState:objects:count:]`](https://developer.apple.com/documentation/foundation/nsfastenumeration/1412867-countbyenumeratingwithstate) on the `NSCarbonMenuImpl` object's array of menu items. I bet this is where the "mutation" error is thrown.
`-[NSCarbonMenuImpl _menuLostMainMenuStatus]` calls [`-[NSFastEnumeration countByEnumeratingWithState:objects:count:]`](https://developer.apple.com/documentation/foundation/nsfastenumeration/1412867-countbyenumeratingwithstate) on the `NSCarbonMenuImpl` object's array of menu items. I bet this is where the "mutation" exception is thrown.