(also hard restart, cold reboot)
A hard reboot is the process of restarting your device after its power has been completely switched off. A manual hard reboot will restart unresponsive devices and clear their working memory (RAM), but doing so will delete all of the user’s unsaved data.
Not all hard reboots are intentional — for example, the device may be forced to shut down due to a power outage.
Performing a hard reboot will result in the loss of unsaved data, so it should only be used as a last resort when a device becomes completely unresponsive. In all other cases, it is preferable to use a soft reboot — letting the device restart without shutting the power down. Initiating a soft reboot from your operating system’s interface lets the device save all your data before restarting.