App Crashes on Enabling Camera Access from Settings iOS 8

App crashes in background while changing permission - swift

Your app is not crashing its just forced to restart by iOS with new privacy settings. So when you change the camera permission then it means privacy policy changed, so app will be killed if its attached to debugger else it will relaunch.

Also, Not only camera permission If the user at some point changes the Address Book, Calendars, Reminders, Camera, or Photos permissions, iOS will SIGKILL the app. (it's default behaviour of iOS)

Watch App get killed while allowing/disallowing camera permission on iPhone App

Your app is not crashing its just forced to restart by WatchOS with new privacy settings. So when you change the any permission in iPhone then it means privacy policy changed, so app will be killed if its attached to debugger else it will relaunch. its happing on both Apple Watch and iPhone. if you change the permission in Apple Watch iOS app will restart. if you change the permission in iOS app Apple Watch app will be restart.

Also, Not only camera permission If the user at some point changes the Address Book, Calendars, Reminders, Camera, or Photos permissions, WatchOS app will SIGKILL the app when change App permission in iPhone. (it's default behaviour of iOS and WatchOS)

Please refer the below links

App killed by SIGKILL when changing privacy settings ,
https://developer.apple.com/forums/thread/64740,
App crashes in background while changing permission - swift,
App crashed in iOS 6 when user changes Contacts access permissions

Crash when toggling access to Camera and Photos

It's not a crash per se. The iOS system terminates every app system wide that has requested access to the Photo Library when that privacy flag is changed (including Apple System Apps).

This originates due to a privacy change made in iOS 6. Look at page 24 in the WWDC 2012 session on Privacy Support in iOS and OS X.

Camera Access Request fails - but ONLY the first time the camera is accessed Swift 3

When you seek user permission through an AVCaptureDevice.requestAccess request, iOS presents an alert dialog that incorporates the message you create in the info.plist. When the user grants permission, it appears as thought iOS then treats the app as if it were returning from the background (even though it does not disappear). That was my issue. I had structured a login sequence to activate whenever the app returns from the background as part of the security. I had disabled that interface for testing - hence the failures. I hope others will find this useful.

Crash when Calendar permission changes outside iOS app

It is an expected behaviour for iOS, when you change its permissions in settings. If the app was opened, the system will send "Message from debugger: Terminated due to signal 9" and the user has to start app manually again.

And I believe there are many similar questions on SO.
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Launched application settings but updating app permission crashing the app

No you can't... Any change in any of your app permission (from the settings) Your app is killed and next time when you launch your application either from app switcher or from the app icon it starts a new process. This is how it works in IOS.

Also See this answer.

Prevent AVCaptureSession from crashing once user toggles Camera privacy settings

No, there is nothing to do about this; this behavior will always cause the app to crash. The same thing occurs when you enable/disable Privacy options for letting an app search the iOS contact book, etc. If the user declines the initial Privacy request, and minimizes the app and goes to the Settings app and changes the Privacy setting, you will see that the app relaunches the next time you come back to it. This occurs any time you make a change to a Privacy setting for your respective app.