This video guide contains directions on how to fix Cortana/Windows 10 Search bar turned white issue. Learn more?
Solution & Goal
Change your system location temporarily.
Step 1: Settings > Time & Language > Region & Language. Step 2: Now, select some another options from the drop down menu. (Location where Cortana is NOT available currently.) Step 3: Close the window and sign out from your account. Step 4: Reboot. Step 5: Sign back in to your account. Step 6: Repeat Step 1 and change location to your own country.