Why does Microsoft Outlook keep asking for Password

First, go to Windows Settings (press Win + I ), > Windows Update > Advanced Settings and turn on the ''Receive updates for other Microsoft Products'' after that start Windows Update and wait for Windows to get the updates and restart your computer.

Then open regedit with administrator account (windows search > regedit > right click > run as administrator), then follow the path
Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity
if there is a EnableADAL Dword Value change it's value to 1, if there is not, create a new ''DWORD (32-Bit) Value'' and name it ''EnableADAL'' without quotes. Double click it and choose Hexadecimal as base, change its value to 1. Close regedit, close Outlook and restart your computer. When your computer opens try to get windows updates and open your Outlook again. Maybe this solution helps.

PS: In regedit path ''16.0'' maybe different in your computer, like ''15.0'', select the path which includes Common and Identity in it.

I think I have finally found the solution. I have tried many different things but this seems to have done the trick:

1. Close Outlook. Open Task Manager and click on the "details" tab. Make sure Outlook is not there. If it is, click on it and click "end task"
2. Click the start button and type "credential" in the list that populates, there should be "Credential Manager". Open it. At the top there should be two categories. "Web Credentials" and "Windows Credentials". Click on "Windows Credentials". Find the credential that is associated with the trouble email account and delete it.
3. RESTART YOUR COMPUTER.
4. Open Outlook. You should be good to go. If Outlook prompts for a password again, type it in and make sure to click the "remember my password" checkbox. It didn't ask for mine.

I tried this several times WITHOUT restarting the computer and it would just come back. This time it seems (so far) to have fixed it.

This doesn't work on my end.. Only my main email address (a non-Outlook.com email address) shows under Windows Credentials, My Outlook.com email address (the one that Outlook sometimes asks for my password when I have Outlook 2019 open) is not showing anywhere in this list.

"First, go to Windows Settings (press Win + I ), > Windows Update > Advanced Settings and turn on the ''Receive updates for other Microsoft Products'' after that start Windows Update and wait for Windows to get the updates and restart your computer.

Then open regedit with administrator account (windows search > regedit > right click > run as administrator), then follow the path
Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity
if there is a EnableADAL Dword Value change it's value to 1, if there is not, create a new ''DWORD (32-Bit) Value'' and name it ''EnableADAL'' without quotes. Double click it and choose Hexadecimal as base, change its value to 1. Close regedit, close Outlook and restart your computer. When your computer opens try to get windows updates and open your Outlook again. Maybe this solution helps.

PS: In regedit path ''16.0'' maybe different in your computer, like ''15.0'', select the path which includes Common and Identity in it."

Has anyone tried this Registry modification suggestion from Süleyman? If so, does Outlook 2019 still ask for your outlook.com email account password sometimes? Wanted to get some feedback from someone who tried it before doing it on my end.

Doesn't work for me. When I get to credential manager under window credentials there is nothing stored. But thanks for sharing. I hope it works for you because it's damn frustrating.