The app's Info.plist must contain an NSMicrophoneUsageDescription key with a string value explaining to the user how the app uses this data

Got a build rejection The app's Info.plist must contain an NSMicrophoneUsageDescription key with a string value explaining to the user how the app uses this data.

The app does not use microphone. Or so I think.

How do I track down where mic is used?

UPD23112016: given that the lazy answer is being upvoted I've filed a new feature request with apple to close this security hole.

UPD05042017: it is still bothersome that once you proxy mic access into some 3rd party framework via some half baked NSMicrophoneUsageDescription you have zero control on where and when it can be used if user agrees to allow mic access. Folks, please do due diligence and craft precise NSMicrophoneUsageDescription that reflects on the fact that the mic is used by the code that's completely outside of your control when the usage is obscured by a 3rd party binary-only framework. Thanks.

UPD2021: Apple did what they could with audit trail for shared resource (such as mic) usage in the latest iOS so the users have some recourse checking when actual access has happened. Nice try, but how many are gonna do the due diligence though?

For the lazy:

if you want to quickly add usageDescriptions for most media access (on-device photos, camera, video recording, location):

right click your info.plist file and -> open as -> Source Code

then paste the following between the current values:

<key>NSMicrophoneUsageDescription</key>
<string>Need microphone access for uploading videos</string>
<key>NSCameraUsageDescription</key>
<string>Need camera access for uploading images</string>
<key>NSLocationUsageDescription</key>
<string>Need location access for updating nearby friends</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>This app will use your location to show cool stuffs near you.</string>
<key>NSPhotoLibraryUsageDescription</key>
<string>Need photo library access for uploading images</string>

These descriptions, of course, are up to you. I tried to make them as generic as possible.

Hope this saves someone's time!

Just add NSMicrophoneUsageDescription key & in value add the justification that why your app is using Microphone. This is the latest requirement in iOS 10.

And the culprit was (drums) : Instabug framework. They tell you right there on their marketware pages they allow users to take audio notes during feedback composition. So I've added NSMicrophoneUsageDescription into the app plist explaining that.

Note that there is a lot of apple API that instabug uses

Undefined symbols for architecture arm64: (i've removed some that seems legitimate according to what that framework claims to do and left what I see no claims for in the marketware)

"_AVMakeRectWithAspectRatioInsideRect", referenced from: +[IBGIAMImageAttachmentView sizeForContent:forWidth:] in InstabugHost_lto.o

"OBJC_CLASS$_CTTelephonyNetworkInfo", referenced from: objc-class-ref in InstabugHost_lto.o

"_AVNumberOfChannelsKey", referenced from: -[IBGVoiceNoteManager startRecording] in InstabugHost_lto.o

"_CTRadioAccessTechnologyHSDPA", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"_CTRadioAccessTechnologyGPRS", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"_CTRadioAccessTechnologyWCDMA", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"_CTRadioAccessTechnologyEdge", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"_CTRadioAccessTechnologyCDMA1x", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"_CTRadioAccessTechnologyCDMAEVDORevA", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"_CTRadioAccessTechnologyCDMAEVDORevB", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"_CTRadioAccessTechnologyLTE", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"OBJC_CLASS$_AVURLAsset", referenced from: OBJC_CLASS$_IBGAsset in InstabugHost_lto.o

"OBJC_METACLASS$_AVURLAsset", referenced from: OBJC_METACLASS$_IBGAsset in InstabugHost_lto.o

"_CTRadioAccessTechnologyCDMAEVDORev0", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

"_CTRadioAccessTechnologyHSUPA", referenced from: +[IBGInspector getCarrier] in InstabugHost_lto.o

ld: symbol(s) not found for architecture arm64

So in this post-Snowden world I have to wonder why does it need coretelephony, for example.

So what I'm getting at is that if you do not have the source the a 3rd party framework you have to disclose to the user that your app itself is NOT using microphone, or camera so that the user has an option of denying access to that device.

You don't want to be in the news someday due to some security flaw exploited via YOUR app.

Unresolved: The carefully crafted microphone usage description does not solve the issue with security completely though in case your app DOES use microphone and a 3rd party framework (think that it) needs it too. You'd have to craft a lengthy description outlining the risks.

Here's where credits disclosure could come handy giving users an idea which 3rd party code your are relying on. Give the credit where it's due :^)

If you are lazy such as myself and never read through the ios security whitepaper here's a short https://developer.apple.com/videos/play/wwdc2016/705/

In case you have no desire to watch the video in its entirety: around 19:00 mark the speaker tells you explicitly that you must not be lazy with those descriptions (you are responsible for a 3rd party code potentially abusing the permissions user has granted to your app. gotta love the binary frameworks ;^)

iOS apps require the user to grant permission before accessing the Microphone. Trying to access it without user permission will lead to app crash.

To request user permission, we just need to add NSMicrophoneUsageDescription key in the info.plist file & and provide a value for this key. Value can be any string stating the applications need to access the microphone.

Instabug uses NSMicrophoneUsageDescription to allow your users record a voice note about a bug or a feedback to you.

Just having AVAudioSession.sharedInstance().requestRecordPermission() somewhere in your code base is enough to trigger this error with iTunes Connect. It's not even necessary to actively call that code!

I guess this warrants yet another answer to compliment the other voluminous answer of mine (cause people are often too lazy to read anyways and developers are mostly people so far)

Apple has acted up upon the security hole of 3rd party binary only frameworks requesting access to microphone and added an audit trail to (among other things) microphone usage in ios15. App Privacy Report it's called in settings. Thusly part of the responsibility to audit that trail is shifted towards the users of the app that has 3rd party junkware embedded. Amen.