Enable/Disable Pre-OS

Pre-OS can be considered as an alternative of WinPE bootable disk. So it can also help you recovering system when unexpected failure occurs.

Switch the status of Pre-OS between Enable and Disable.
The name of the button depends on the current status of Pre-OS. If Pre-OS is currently enabled, the button will be Disable Pre-OS. 

Once the Pre-OS enabled, you will get a EaseUS boot menu when computer boots. After select it, you will get into EaseUS Todo Backup instead of Login Windows.

There are two kinds of Pre-OS environment for different editions, and It is based on the different bootable disk environment you used.

Linux Pre-OS
It is based on Linux environment and only contains basic Recover and Clone options.

Windows Pre-OS
It is based on WinPE environment and nearly all features are available in this environment.