Northstar doesn't open on Windows 10

Affected Platform

Problem

Opening Northstar flashes a pop-up but the Login window never appears. Windows 10 is silently blocking Northstar from opening, without providing any warning or error message.
Unfortunately, this a bug with Windows 10 itself. After upgrading to Version 1803 or later users will need to make a change to their Windows settings in order to allow Northstar to start normally. There is currently no ETA on when Microsoft will release an update that fixes the issue.

Solutions

Option 1: Manually disable the Windows 10's 'Smart Screen' feature that is blocking Northstar from opening.
1. In the Start Menu, search for and open "Windows Defender Security Center"
2. Click the "App and browser control" tile
3. Set the "Check apps and files" setting to "Off"
Option 2: Automatically disable the Windows 10's 'Smart Screen' feature that is blocking Northstar from opening.
1. Download and run this file: Northstar_DisableSmartScreen.reg. Accept the warning prompt and it will make a Windows Registry change that toggles the exact same setting as Option 1.
2. To undo this change, download and run this file: Northstar_UndoDisableSmartScreen.reg

Notes

These Solutions are temporary workarounds that bypass an important Windows feature. After Microsoft release an official update to unblock apps like Northstar then please be sure to re-enable the SmartScreen option.

References