Help removing an unwanted Microsoft account from a local user

Hi,
as part of improving the collaboration between some of our local tennis club committee members, I received an invite to join a family group. I thought it might allow us to share emails and calendars etc. So I clicked on the Join Now now button. I initially thought that it had not worked, probably as a result of me providing an email address that was not a Microsoft one, so didn't think too much about it. However, a couple of days later, when I clicked on the Start button and clicked on my name to sign out, it came up with the tennis club's chairperson's name and her new Outlook email address. If I click on the link 'My Microsoft Account', it takes me to the login for her Microsoft account. Previously, I had only used my user account as a local user - not tied to any email address. A similar set-up on my laptop brings up the Microsoft account that I use purely for syncing files to Onedrive, so I assume that the same would have happened on my PC prior to this.

I've tried all sorts of avenues to remove this link between her Microsoft account and my local user to no avail, including going into the Family safety page and removing my pending invite. I've even resorted to attempt a system restore to a date before I clicked on Join Now button, but no change.

Does anyone know how can I remove her Microsoft account from any association with my local PC account?

TIA
BR

BorderReiver said:

However, a couple of days later, when I clicked on the Start button and clicked on my name to sign out, it came up with the tennis club's chairperson's name and her new Outlook email address

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As well or did it replace yours? I’m assuming as well. Follow the above tutorial.
It sounds a little suspect.

BorderReiver said:

I received an invite to join a family group

Click to expand...

My apologies, try this:

if you have admin permissions, create and use local account. They supposedly loosened restrictions on this in the last couple of years, but I haven't tried. It was or is tied to a Hotmail account. I thought they removed that requirement. someone else can chime in.