Performing a hard reset will remove all data including the Google account, system data, app data, app settings, and downloaded apps. Only perform a hard reset if absolutely necessary.
Pictures, Videos and Music will also be removed. It is recommended to backup this data.
Personal data such as Wi-Fi passwords, Browser bookmarks, User dictionary, a list of installed Google Play Store apps and other customized settings can be backed up to and restored from Google's servers.
Disable Automatic Restore prior to performing a hard (factory) reset when attempting to determine whether a 3rd party app is the cause of an Operating System / App issue.
Fast Power-on must be disabled.