One of the problems we have had to face in windows 8, 8.1, and 10 is that the old ways of booting into safe mode no longer work- F8, Shift+F8 , etc do not work anymore. These processes do not work anymore because the boot sequence has become faster than ever before. This does not mean that the safe mode no longer exists, it simply means the process for getting into has changed. Here is how to go about it.
From your windows search, type run and hit the enter key.In the dialog box that appears, type msconfig and hit the enter key
Click on the boot tab and check the box for safe boot. Apply and ok. Windows will prompt you for a restart. Its ok! Allow it.
Source http://www.timigate.com/2016/01/how-to-boot-to-safe-mode-in-windows-10.html#more