Once your build '''reaches the license expiration date''', your computer will automatically reboot approximately every 3 hours. As a result of this, any unsaved data or files you may be working on, will be lost.
The computer will '''no longer boot''', 2 weeks after the license has expired. After the expiration date is crossed, when you start your computer, you will see a '''Recovery message – Your PC/Device needs to be repaired''' message. You will not be able to log in to your computer. In this case, you will have to [https://www.microsoft.com/en-hk/software-download/windows10|download the ISO file] from another computer and then transfer the ISO file to some installation media. Once you have done this, you will have to boot the computer from the installation media to install the latest build of Windows 10.
You should always [https://www.minitool.com/help-sm/backup.html|backup all your data] and check your Windows Update to see if any new build or upgrades are available.