Why does Xiaomi 1 1 Youth Edition delete information still exist?

1. Check whether to delete the old information settings, Info, More, Settings, More Settings-,delete the old information, and close.

2. If it has been turned off, please check whether the third-party SMS software is installed in the mobile phone and check whether there are relevant settings.

3. If the mobile phone still automatically deletes the SMS, please back up the contact, information, photos and other data. And try to restore the machine to factory settings.