Try going to MS security update, this happened to me and caused me a lot of pain,it is a worm virus and the security update did the trick and stopped the shutdown,
this is the MS link/page:
Surface Pro 5 News - release date, UK price, features, specs
Microsoft Surface Studio hands-on review: the iMac killer is here
Best Mac antivirus 2017
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.