[ms office - 2019] Desktop Outlook suddenly won’t open.

[mp4-dave]

This is a very odd problem that’s started over the half term.

 

No staff users can open Outlook 2019, which worked perfectly before the half term. When they click on the icon they’re asked for their username and password, no matter how many times they enter it, the box comes back again. If you click Cancel then you get a blue Outlook 2019 loading screen with “loading profile” in the bottom left hand corner and nothing happens.

 

It works perfectly for IT admins, but not for any staff users.

 

If you log on as an admin you can add one of the not working email accounts to Outlook and it works perfectly straight away so it seems like a permissions issue, but I have no idea where or why it has changed over the half term.

 

All staff users are affected by this but can log on to the web version with no issues.

 

Has anyone ever seen anything like this or got any ideas of what I can try? Two of us spent all day yesterday working on it and while we’ve narrowed it down, we don’t seem any closer to a solution.

[ifarmery1234]

You didn't previously disable Modern Authentication in the registry/Group Policy by any chance? Microsoft disabled Legacy Auth just before Half Term and I had a machine where the EnableADAL was set to 0 causing us this issue.

 

Location is HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\

Edited November 1, 2022 by ifarmery1234

[mp4-dave]

Thanks for the suggestion ifarmery1234, when logged on as an admin I can see that that registry key doesn't exisit. When logged in as a normal user I can't open the registry.

When logged on as an admin with Outlook working I can Ctrl+right click on the Outlook icon in the system tray and see that it is using Bearer authentication which is the modern version.