OnePlus
Factory Reset: Erase All Data auf OnePlus
A factory reset restores your OnePlus phone to the state it was in before you signed in for the first time. It removes every account, app, and system setting added since setup, because Android and OxygenOS keep this data in dedicated partitions that a simple restart or cache clear never touches.
Use this option when performance problems persist after other fixes, when preparing the device for resale, or when a broken update leaves the system unstable. If you only need to fix one misbehaving app or free up storage, clearing that app's cache or data is a lighter alternative that keeps your accounts intact.
To start the reset, open Open the Settings ➔ Tap on System ➔ Tap on Reset options ➔ Tap on Erase all data (factory reset) ➔ Tap on Erase all data ➔ Tap on Confirm. The phone reboots automatically once the process finishes, which can take several minutes depending on how much data is stored on it.
Afterward, the device asks you to sign in with a Google account. If the phone was linked to Find My Device beforehand, it may require the previous owner's credentials, so keep them ready to avoid getting locked out. Local files that were never backed up to the cloud are removed permanently, so save photos, messages, and documents before you confirm.