New Outlook - We ran into an error - Assertion: AccountSourceListStore is not initialized

Question

I recently hybrid-joined my devices into Entra ID (not mdm), when users are starting to set up New Outlook on new devices, they are running into an error called:

Error: Assertion:AccountSourceListStore is not initialized at r

Answer 1

A forced update for “Outlook New” fixed the problem for us:

%localappdata%\Microsoft\WindowsApps\Microsoft.OutlookForWindows_8wekyb3d8bbwe\olk.exe --force-update

Answer 2

Hi @Carlos Gomez  

Thank you for posting your question in the Microsoft Q&A forum.  

Please note that our forum is a public platform, and we will modify your image to hide your personal information in the description. Kindly ensure that you hide any personal or organizational information the next time you post an error or other details to protect personal data. 

The error message Assertion: AccountSourceListStore is not initialized is not specific to your tenant, MDM, or hybrid‑join configuration. It occurs during the Outlook WebView boot process when the local Outlook WebApp components fail to initialize a required module before launch. 

Hybrid‑join itself does not directly cause this issue. However, if the device is joined but hasn’t yet completed PRT (Primary Refresh Token) acquisition, or if the user signs in before the WebView runtime and Web Account Manager (WAM) token infrastructure have fully initialized. 

Here are some steps you may try: 

1.On an affected device, run the following command: 

dsregcmd /status 

Verify that the following values are set to YES: 

-AzureAdJoined  

-DomainJoined  

-AzureAdPrt  

Reference: Troubleshoot devices by using the dsregcmd command - Microsoft Entra ID | Microsoft Learn. 

2.Refresh the sign-in session

-Sign out of Windows.

-Reboot.

-Sign back in.

-Launch New Outlook again.

I hope this helps. 

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