Get-TeamsOwnerlessTeamsReport

<#
.SYNOPSIS
    Finds teams with no active owners.

.DESCRIPTION
    Checks every Microsoft 365 group backing a team and flags any with
    zero owners, which happens more often than expected once the
    original creator leaves the organization, leaving the team with
    nobody able to manage settings or membership.

.EXAMPLE
    .\Get-TeamsOwnerlessTeamsReport.ps1

.NOTES
    Requires Microsoft.Graph.Groups and Microsoft.Graph.Teams with an
    active Connect-MgGraph session.

.AUTHOR
    Shehryar Hassan
#>

$teams = Get-MgGroup -Filter "resourceProvisioningOptions/Any(x:x eq 'Team')" -All

$ownerless = foreach ($team in $teams) {
    $owners = Get-MgGroupOwner -GroupId $team.Id
    if ($owners.Count -eq 0) {
        [pscustomobject]@{
            TeamName  = $team.DisplayName
            GroupId   = $team.Id
            CreatedOn = $team.CreatedDateTime
        }
    }
}

if ($ownerless) {
    $ownerless | Format-Table -AutoSize
    Write-Warning "$($ownerless.Count) team(s) have no active owner."
} else {
    Write-Host "Every team has at least one owner." -ForegroundColor Green
}