Hi @ChrisEaker,
Welcome to Microsoft Q&A forum.
Thank you for reaching out and providing details about the issue where the “Account switched” message appears when switching between mailboxes in Outlook 365 using Microsoft Edge.
This behavior typically occurs because Outlook on the web uses a shared authentication session within the same browser profile. When multiple Office 365 accounts are opened in separate windows under the same Edge profile, the authentication token can switch between accounts. This results in the prompt you are seeing.
To better assess and address the issue you're experiencing, could you kindly provide the following details:
- Is the user accessing the group mailbox by signing in directly, or is it added as a shared mailbox in Outlook?
- Does the issue persist when using InPrivate mode or a different browser (Firefox or Chrome)?
- Has the user tried using separate Edge profiles for each account?
In the meantime, here are some workarounds you can try to help resolve the issue:
1/ Use different browsers for each account:
- Sign in to your primary mailbox in Microsoft Edge.
- Open the group mailbox in a different browser (e.g., Chrome or Firefox).
2/ Add the group mailbox to Outlook web:
- Open Outlook on the web and sign in with the user's account
- Click the setting icon next to the profile > select Account > Shared with me > Click the button "Add" and add the group mailbox.
Note: Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.
I hope this helps resolve the issue with switching between accounts for your user. I'm glad to assist and truly hope the information provided has been useful. Please feel free to reach out anytime if you need further assistance.
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