NOTE: In case your phone doesn’t work properly, you might be able to solve this behavior by factory resetting the device. WARNING! When you master reset your phone, all personal data stored on the internal memory will be deleted, including photos, ringtones, downloaded content, contacts etc. Furthermore all settings will be restored to factory values.

NOTE: Visit this thread to learn how to back up and restore data on the Xperia M5 before a factory reset.

Master Reset via Settings:

  1. Tap “Apps” on the home screen
  2. Open “Settings”
  3. Tap “Back up & reset” under “Personal”
  4. Clear the “Automatic restore” check box
  5. Under “Personal data”, tap “Factory data reset”
  6. Tap “Reset phone” and if necessary, enter your PIN / password / pattern and tap “Continue”
  7. Tap “Erase everything” to confirm

Force-Shut-Down the Device:

NOTE: In case your phone freezes and is unresponsive, you can force shut down the device by performing the following:

  1. Detach the SIM cover
  2. Remove the memory card slots
  3. Use the tip of a pen or similar object to insert it the “OFF” button (NOTE: Don’t use objects that are too sharp or you might damage the button)

Reinstall the OS Via PC Companion (Windows Computer):

  1. Open the Internet browser on the computer
  2. Visit https://support.sonymobile.com/globa.../pc-companion/ and install PC Companion
  3. Once installed, open “PC Companion”
  4. Click “Start” under “Support Zone”
  5. Under “Phone / Tablet Software Update”, click “Start”
  6. Connect the Xperia M5 to your computer via USB
  7. On the computer, click “repair my phone / tablet”
  8. Follow the on-screen instructions to reinstall the OS

Reinstall the OS using Sony Bridge for Mac:

  1. Open the Internet browser on the Mac
  2. Visit https://support.sonymobile.com/globa...ridge-for-mac/ and install the app on the Mac
  3. Connect the phone to the Mac via USB
  4. In Sony Bridge, click “Xperia” > “Repair Xperia device”
  5. Click “Continue” and follow the on-screen prompts to complete the process

Reset via Dialer:

NOTE: Another method you might be able to use for resetting the Xperia M5 is through the phone’s dialer. To try this method:

  1. Open the “Phone” app
  2. Tap the “Dialer” if necessary
  3. Enter *#*#7378423#*#*
  4. A menu should pop-up on the screen. From there, tap “Customization Settings” > “Reset customization”
  5. At the “data will be cleared and factory data reset will perform” message, tap “Reset customization and reboot”
  6. Your device should now reboot and reset all data


› See More: Sony Xperia M5: Factory Reset and Reinstall the OS via PC Companion / Sony Bridge