Outlook not recognizing M365 accounts after setting up New Outlook

Question

After accidentally clicking on New Outlook on a machine that already has M365 installed, a user has set up New OLK but it did not recognize their M365 login. Other apps like Word and Excel still recognize the M365 account, but any attempt to return to the old Outlook prompts the user to create a New OLK profile, which also no longer recognizes the M365 user account. New Outlook has since been uninstalled, the machine has been rebooted, and updates have been checked, but the user is still unable to recreate an OLK profile via the OLK OLD shortcut or by using Mail in Control Panel. As a side note, the customer is concerned about the impact on sites that have heavily invested in OLK automation and wants to know if the entire organization can expect the same result.

Answer 1

Hi @Shane King ,

Welcome to our forum!

a user has set up New OLK but it did not recognize their M365 login.

What's the version of your Outlook?(File>Office Account>About Outlook)

And what do you mean that "not recognize their M365 login"? Is there any error prompt? If possible, please provide a screenshot of your case for our better research. (In order to avoid the privacy leakage, please remember to hide your personal information.)

but any attempt to return to the old Outlook prompts the user to create a New OLK profile, which also no longer recognizes the M365 user account.

Do you mean that you want to turn off New Outlook to switch to Legacy Outlook?

If so, according to your description, i notice that you receive the guide to "create a New OLK profile“, it's suggested that you could try to follow the below steps:

1.Control Panel>Show Profiles...>Add...>type a name for the new profile>Ok.

2.Fill in the information of your email account to configure your account>Next.

3.After you add your account successfully, you can get back to Mail window to select how profiles displayes:

• If you select "Prompt for a profile to be used", when Outlook starts, you can choose the profile to open.
• If you select "Always use this profile" and confirm the profile, when Outlook starts, the profile will be opened automatically.
  

Hope the above help!

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Answer 2

Hi Christy,

I had mentioned in the question that I had already carried out deleting and re-creating a profile in Mail (32bit) App in control Panel. I was provided with a powershell script to assist with the error, but later found it was an M365 wide issue.

Thanks.