How to initialize your Android smartphone and reset it to the factory state [2019 version]

I bought a new Andorid smartphone and no longer need the smartphone I've been using. In such a case, it is advisable to initialize (reset) your smartphone to reduce the risk of personal information leakage. It is also an essential task when handing over an old smartphone to family and friends.

* This article introduces how to operate a smartphone equipped with Android 7.0 or later OS. The screen configuration, menu names, setting items, etc. may differ depending on the Android OS version and model.

First, delete your Google account and erase your personal information

To delete personal information from your Android smartphone, first delete your Google account. If your Google account is set, various information such as your address and contact information will remain on your device. Here, we will show you how to delete your Google account using Xperia XZ Premium (updated to Android 9). You should be able to follow almost the same procedure on other smartphones.

Initialize your Android device and delete all settings and data

When transferring or selling a smartphone to a third party, it is safe to initialize all accounts, data, and various settings, and return the smartphone to the factory state. Initialization can be executed from "Settings" → "System", but be careful not to execute it on your smartphone as it will erase all the data so far.

If the "device protection function" of Android 5.1 or later is turned on, the unlock operation is required when performing initialization. If you initialize with the device protection function turned on, you will not be able to start it unless you log in with the original Google account. If you want to transfer it to another user, it is safe to delete your Google account in advance and then perform initialization.

SD card format is a separate task

Even if the Android smartphone is initialized, the data on the microSD card that was installed remains. If you also want to erase the data on the microSD card, it is recommended to format the SD card from "Settings" → "Storage". Of course, if you take out the microSD card from your old smartphone and continue to use it on your new smartphone, you don't need to format it.