Wiping the Cache Partition:

In case you have issues with your phone, is unresponsive, it freezes, constantly resets etc. then you might want to try applying a factory reset and see if that fixes the issues. However, before doing so, it's recommended that you first wipe the cache partition, as doing so will not result in data loss. To wipe the cache:

  1. With the Xperia powered on, press and hold the "Power" and "Volume Up" buttons at the same time
  2. The screen will turn off and the phone will vibrate once, after about 3 seconds
  3. Once the screen turns off, release the buttons
  4. Press the "Power" key to turn your smartphone back on

Master Resetting From the Settings Menu:

If wiping the cache partition didn't help, then you might have to apply a factory reset. WARNING: master resetting your device will result in loss of personal data stored on the internal memory, including downloaded content, apps, photos, ringtones as well as contacts. However, a factory reset will not affect data stored on the SIM or SD card.

  1. If necessary, back up any important data stored on your phone's internal memory
  2. While on the home screen, tap the "Applications" icon
  3. Go to "Settings"
  4. Tap "Back up & reset" under "Personal"
  5. Uncheck the "Automatic restore" check box
  6. Scroll to "Personal Data" and tap "Factory data reset"
  7. Tap "Reset phone". Assuming that you've set a PIN or password, you'll need to enter it and tap "Continue"
  8. Select "Erase everything" to confirm

Master Resetting Via Hardware Keys:

IMPORTANT: master resetting via the hardware keys is not available on the Xperia Z1 Compact. However, if your device can't be reset from the settings menu as it might freeze or not boot completely, you can try performing the following steps:

  1. Press and hold the "Power" and "Volume Up" buttons at the same time
  2. Continue to hold these keys for about 10 seconds, until your device vibrates three times
  3. Once that happens, release the buttons
  4. Press the "Power" button and try rebooting your device as you normally would

Booting in Safe Mode:

Assuming that the problem that you have resides in a 3rd party app that prevents you from uninstalling it, then you can try and reboot your device in safe mode and uninstall the app from there. NOTE: in safe mode, all 3rd party apps are disabled.

  1. Press and hold the "Power" button
  2. Tap and hold "Power off"
  3. When you get the safe mode prompt, tap "OK". Your device will now reboot in safe mode
  4. Once the device boots up, tap the "Applications" icon from the home screen
  5. Tap "Settings"
  6. Scroll to "Device" and tap "Apps"
  7. Swipe the screen until you reach the "Downloaded" category
  8. Select the app that causes problems and tap "Uninstall"
  9. Tap "OK" to confirm

NOTE: To exit Safe Mode, press and hold the "Power" button, tap "Power off" and press the "Power" button to reboot your device as you normally would

See More: Sony Xperia Z1 Compact: Clearing the Cache Partition, Factory Resetting and Booting in Safe Mode