[Android only]

A: Make sure Settings -> Service option is switched off.

After leaving the UI Neutron will close its process within around 5 minutes (depending on the running background tasks) automatically. There are background tasks which block self exit: source refreshing or scanning, music playback, wake timer, normalization queue, license checking. On Android 8+ all background tasks are reported in the Ongoing Task notification, you can close Neutron quickly via the notification by pressing [X] button.