SharedPreferences not persistent

I am using a SharedPreferences in Android.Everything works great in the same session.

However once I relaunch the application, all of the preferences that were set from the previous session are lost.

Is there anything I need to specify to tell the SharedPreferences to hang around from run to run?

I am creating the preferences by calling

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);

Then I set properties by e.g.

preferences.edit().putString(key, value);

and I get it by

preferences.getString(key, defaultValue);

Thanks, Victor