MacOS "Another account from your organisation is already signed in on this device"

I am the admin of my Microsoft 365 tenant. My license is used on MacOS, Windows 10, Windows 11 and Android. This issue just appeared this morning on my office iMac running Monterey 12.6.2 and Office apps versioned 16.70.

The error that another account is signed in is a red herring. The Office-Reset License and Sign-in reset did not work in this case. Office-Reset was used to remove Office completely. It was then re-installed, and the same version 16.70 is what downloaded from Microsoft. It's working fine now.

I don't know what the cause of this issue is, But I do know what it's not. It's not because another 365 user was logged in on the same device as the error message indicates.

Hi, The root cause was related to a shared mail box, I removed it from Outlook, and used office-reset tool to repair sign-in issue.

I had been having similar problems on several clients' computers and this "office-reset" tool fixed them.

Many thanks!

I have been having the same issue for the last two days.

I've done all the steps, all the removal tools, all the reboots, all the complete uninstall and reinstalls.

I thought I had it figured out after running this script to do a deep uninstall, following the additional steps and reinstalling:

https://github.com/jimye/OfficeUninstall

Was working fine and was adding everything back, when I got a popup message like this:

And boom I'm back in the same boat:

This is beyond frustrating folks - I've wasted hours on this over the past couple of days and Office is unusable.

Microsoft Support team please help!

Thanks for everyone's continued assistance.

Steve

I just solved the issue for myself.

For me, the issue was that, due the nature of my job, I have multiple accounts for different tenants. I was working on an Excel file in a client's tenant and I had signed into Excel using that account. When my password was reset (by policy) at work, all of the Office desktop applications needed me to re-login but, for some reason, they would not show me who I was logged in as or give me the ability to swap or logout.

After shutting down all of my Microsoft apps (Teams, OneDrive, Edge, Office, etc.), I ended up searching for "Office" and "Microsoft" in my Keychain Access and deleted everything I could find.

After that, I was able to open PowerPoint and tried signing in using my work account. This time, it accepted my credentials without complaint but, when PowerPoint refreshed, it actually showed me that client account I had been previously signed in. Thankfully, it finally allowed me to sign out, which immediately swapped in my primary work account.