Also, clear the radio FM app data and then try to boot on safe mode.
1. Tap the Application screen icon.
2. Find and tap Settings > Apps.
3. Swipe to the All tab.
4. Find and tap on the radio FM app.
5. Tap Force stop > Clear data.
6. Restart the phone
How to boot on safe mode
http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008How to boot on safe mode on Lolipop
1. press and hold the power key
2. once you get the pop up menu
3. press and hold "power off"
4. Boot on safe mode should become available