Because they like to make it difficult, MS have changed how you get into Safe mode in Windows 10. Like Windows 8, to get into safe mode in Windows 10, reboot the computer and press Shift + F8 as Windows 10 boots up.
As an alternative, you can get into safe mode from the Windows 10 operating system (requires a reboot) by running the following command then rebooting and chosing safe mode:
Bcdedit /set {bootmgr} displaybootmenu yes
❗ Note: You have to run the command prompt as an Administrator (CTRL + Right click the command prompt shortcut and choose Run as administrator).
There is a way to get Windows 10 to reboot into safe mode through the GUI, but it’s rather convoluted so if you need it, reply here and I can talk you through booting to safe mode from the Windows 10 GUI.