Have you tried this?
There are a few things you should try first when you experience problems with your device:
- By restarting your device you turn off all running applications and free up memory. This sometimes automatically solves problems with your device . If the device won't restart normally, you can force your device to restart. No settings or personal data are deleted during a forced restart.
To force the device to restart or shut down
- Press and hold down the power key and the volume up key at the same time for 6 seconds.
- Your device vibrates once. Depending on whether you wish to force the device to restart or shut down, proceed as follows.
- If you wish to force restart the device: Release the keys at this point. The device restarts.
- If you wish to force shut down the device: Continue pressing the keys. After a few more seconds, the device vibrates three times and turns off.
- Update your device to ensure that you have optimal performance and the latest enhancements. Read more about how to update and find latest software version.
- Perform a factory data reset. This is sometimes the best solution if your device stops functioning properly. Make sure that you know your Google™ account username and password before you start.
To perform a factory data reset
To avoid permanent damage to your device, do not interrupt a factory data reset procedure.
- Back up any important data that is saved on the internal memory of your device to a memory card or other non-internal memory. If you have any encrypted files stored on an SD card, you should also remove the encryption to ensure you can still access them after the reset.
- Find and tap Settings > System > reset .
- Tap Factory data reset > Reset phone .
- If required, draw your screen unlock pattern or enter your screen unlock password or PIN to continue.
- To confirm, tap Erase everything .
Your device does not revert to an earlier software version of Android when you perform a factory data reset.
- If you can’t access the Settings menu on your device, perform a software repair with the Xperia™ Companion computer application. You can perform a software repair even if your device seems totally unresponsive.
To repair the device software using Xperia™ Companion
If possible, you should always back up all personal data before performing a software repair. All data in the internal memory is overwritten during a software repair. Content on an external SD card is kept.
- Make sure you know your Google™ account username and password. Depending on your security settings, you may need to enter them in order to restart the device after a software repair
- Make sure that Xperia™ Companion is installed on your PC or Mac®.
- Open the Xperia™ Companion software on the computer, but do not connect your Xperia™ device until you're told to in the five-step instruction in the Xperia™ Companion window.
- Select Software repair on the computer screen.
- Follow the on-screen instructions to reinstall the software and complete the repair.