Just installed the latest WIN10-Update and it has a bug (see title). To solve that issue use RegEdit and edit the entries below. If you don't find an entry, create a new Please backup ("export") the Registry before.
Reason seems to be that Cortana somehow stucks in initialization and loops.
Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Microsoft\Windows\ CurrentVersion\Search] "AllowCortana"=dword:00000000 "BingSearchEnabled“=dword:00000001 "„CortanaConsent“=dword:00000000