The device randomly turns off or doesn’t start up properly?

You may experience your device randomly turning off and remaining turned off.

Try these steps one after the other. Check if the issue is resolved after each step before trying the next one.

• If you can power on the device, update it to a new software version using Xperia Companion.
• Remove the SIM™ card, and then try restarting the device. If the device restarts successfully after you remove the SIM card, your SIM card may be damaged. Replace the SIM card.
• Remove the SD™ card, and then try to force your device to restart. If the device restarts successfully after you remove the SD card, your SD card may be damaged. Replace the SD card.
• Restart your Xperia® device in Safe mode. In Safe mode, only software and applications installed when you purchased your device are available. If the device’s performance improves in Safe mode, one or more of your post-purchase downloaded applications are likely negatively affecting it. Proceed by uninstalling any interfering app.
• Perform a factory data reset or perform a software repair using Xperia Companion if you can't access the device. Before performing a software repair, make sure you know your Google™ credentials. Depending on your security settings, you may need to enter them to start up the device after a software repair.
  
  Note: Always back up all personal data before performing a factory data reset. All data in the internal memory is overwritten during a factory data reset. Content on an external SD card is kept.