Why did you switch to test mode?

Question

Windows

Hello. I worked for myself, I did not touch anyone or anything. But after rebooting my Windows 8.1 x64 , an inscription appeared in the lower right corner: " test mode ". Who faced it? Tell me how to solve this?

Answer 1

https://www.google.ru/?gws_rd=ssl#lr=lang_ru&newwi...
https://support.microsoft.com/kb/2509241/ru?wa=wsi...