An unknown contact has somehow merged itself into my hotmail contacts and I am unable to delete from the contacts menu
The info below fixed my problem. Re: Not able to delete spam addresses in Hotmail Contacts.
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Spam issue has become most common these days, so to secure your account and stop these spam contacts that gets added to your account please follow the below steps to avoid this spam issue. To resolve it, please reject the invitation that you get as Invitation pages.
Please follow these steps:
Click on Contacts option.
Then click on View invitations.
Select Groups.
Click on the “No, thanks” thanks option.
This would reject all the unwanted invitations and also avoid spam contacts.