💁 How to delete a guest user in SharePoint Online ?

When a user or guest is in a SharePoint-site, their user information is cached saved in the UserInfo list. If the user or guest is deleted, their related UserInfo information is not deleted.
Their profile is still displayed, which can cause confusion when users do searches in SharePoint. Sometimes guest users remain active in SharePoint.
If you want to solve this you can get started via this blog.
Here's how to delete a guest account using Azure Active-Directory
Navigate to https://portal.azure.com
Delete the guest user

How can you delete a guest through Office 365 portal?
Guests can also be deleted through the regular Office 365 portal.

Thus, you can remove a guest use in SharePoint Online via PowerShell
Connect-SPOService -Url https://yourtenantnamesharepoint.com -Credential $cred
$ExtUser = Get-SPOExternalUser -filter jondoe@fabrikam.com
Remove-SPOExternalUser -UniqueIDs @($ExtUser.UniqueId)
More information can be found here: https://docs.microsoft.com/en-us/sharepoint/remove-users
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