Windows phone crash device.Sensors.ni.dll

I am experiencing some crashes on my app (somewhat similar to a compass app). The windows crash report is telling me this:

frame 0: 
Microsoft.Devices.Sensors.ni.dll; Microsoft.Devices.Sensors.Accelerometer.Start; 0x0000006c    
frame 1:
PivotApp1.ni.DLL; PivotApp1.MainPage+_start_d__0.MoveNext; 0x000001d4    
frame 2: 
mscorlib.ni.dll; System.Runtime.CompilerServices.AsyncMethodBuilderCore._ThrowAsync_b__3; 0x00000036

I am unable to understand what this exactly means here. Based on what I get from it, it is probably because of the accelerometer.

This is my current code and It seems like the error is generated from somewhere in here :

private async void start()
    {
        //Check for the user agreement in use his position. If not, method returns.
        if ((bool)IsolatedStorageSettings.ApplicationSettings["LocationConsent"] != true)
        {
            // The user has opted out of Location.

            MessageBox.Show(AppResources.main_cantuse);

            Application.Current.Terminate();
        }

        else
        {
            //KOMPASS
            if (compass == null)
            {
                // Instantiate the compass.
                compass = new Compass();

                // Specify the desired time between updates. The sensor accepts
                // intervals in multiples of 20 ms.
                compass.TimeBetweenUpdates = TimeSpan.FromMilliseconds(20);

                compass.CurrentValueChanged +=
                new EventHandler<SensorReadingEventArgs<CompassReading>>(compass_CurrentValueChanged);
                compass.Calibrate +=
                new EventHandler<CalibrationEventArgs>(compass_Calibrate);
            }

            try
            {
                compass.Start();
                timer.Start();

                accelerometer = new Accelerometer();
                accelerometer.CurrentValueChanged +=
                    new EventHandler<SensorReadingEventArgs<AccelerometerReading>>(accelerometer_CurrentValueChanged);
                accelerometer.Start();
            }
            catch (InvalidOperationException)
            {
                MessageBox.Show(AppResources.main_unabletostart);                    
            }

I would like to ask, Do I have to check if the accelerometer is ready (or null check or something else) ?

Any help or guidance here is appreciated.

Those crashes are probably from devices that do not have a compass (yes, there are devices like this out there).

You should check for the compass with Compass.IsSupported and only use it when it returns true.