I have a PIP camera that is streaming from the front and back based on AVCaptureMultiCamSession. It works fine, but when i go to swap the camera it crashes. This is code that works with a single camera, so not sure what is wrong. Also the object appears valid in the debugger. This is the snippit where the camera is swapped private func updateSessionConfiguration() { guard isCaptureSessionConfigured else { return } captureSession.beginConfiguration() defer { captureSession.commitConfiguration() } // Remove all current inputs for input in captureSession.inputs { if let deviceInput = input as? AVCaptureDeviceInput { captureSession.removeInput(deviceInput) app_log("removing input for \(input)") } } // Add the primary device input if let deviceInput = deviceInputFor(device: captureDevice) { app_log("device input \(deviceInput)") if !captureSession.inputs.contains(deviceInput), captureSession.canAddInput(deviceInput) { captureSession.addInput(deviceInput) } } if let secondaryDeviceInput = deviceInputFor(device: secondaryCaptureDevice) { app_log("Secondary device input \(secondaryDeviceInput)") if !captureSession.inputs.contains(secondaryDeviceInput), captureSession.canAddInput(secondaryDeviceInput) { captureSession.addInput(secondaryDeviceInput) } } updateVideoOutputConnection() } It crashes at: captureSession.addInput(deviceInput) with: Thread 10: EXC_BAD_ACCESS (code=1, address=0xcaeb36b964f0) which is strange because canAdd is checked prior to this call. Totally stumped here. Please help. Not sure if this is an AVCaptureMuliCamSession issue or something.