Having the exact same issue,
-Tried a clean installation of my gtx 1080
-clean ue4 4.14 copy
nothing is working for me,
hopefully someone will show up with a solution, i will keep digging till then 
Having the exact same issue,
-Tried a clean installation of my gtx 1080
-clean ue4 4.14 copy
nothing is working for me,
hopefully someone will show up with a solution, i will keep digging till then