Default Site Collection Administrators

Question

I have a DEV Office 365 that was not setup by me. I am trying to create new site collections via PowerShell. Somehow, I see a bunch of AD groups and users automatically added as Site Collection Administrators.

Does anyone know how it is possible? I am creating a site collection with a single PowerShell line. It does not make sense that I see all of these site collection admins added. How does it happen?

New-SPOSite -Url $SiteProperties.SiteUrl -Owner $currentUserEmail -Title "Contoso" -TimeZoneId 10 -Template "SITEPAGEPUBLISHING#0"

When I crate site collections via UI, the list of site collection admins is different. It makes me even more confused:

After creating a modern communication site via PowerShell

Creating Classic Team site via UI

Creating Modern Communication site via UI

Answer 1

I cannot reproduce this behavior in my environment. This is the command I use for testing:

New-SPOSite -Url https://tenant.sharepoint.com/sites/newsite -Owner [email protected] -Title "Contoso" -TimeZoneId 10 -Template "SITEPAGEPUBLISHING#0"

And [email protected] is the only Site Collection Administrator in the list.

What if you use single email address directly instead of $currentUserEmail?

And for the following question:

Company Administrator and SharePoint Service Administrator stand for Global admin and SharePoint admin assigned via Microsoft 365 admin center. They are assigned as Site Collection Administrators when creating a classic team site via UI by default (so that they will have access to the classic team sites by default).

This is not the default behavior when creating modern sites via UI.

Reference: SharePoint Administrator Roles demystified.