List all external users in all site collections

Author: Albert-Jan Schot

This script helps you to list all external users in all SharePoint Online sites. It provides insights in who the users are, and if available who they where invited by.

PowerShell

$fileExportPath = "<PUTYOURPATHHERE.csv>"

$m365Status = m365 status --output text

if ($m365Status -eq "Logged Out") {
  # Connection to Microsoft 365
  m365 login
}

$results = @()
Write-host "Retrieving all sites and check external users..."
$allSPOSites = m365 spo site list | ConvertFrom-Json
$siteCount = $allSPOSites.Count

Write-Host "Processing $siteCount sites..."
#Loop through each site
$siteCounter = 0

foreach ($site in $allSPOSites) {
  $siteCounter++
  Write-Host "Processing $($site.Url)... ($siteCounter/$siteCount)"

  Write-host "Retrieving all external users ..."

  $users = m365 spo user list --webUrl $site.Url --output json --query "[?contains(LoginName,'#ext#')]" | ConvertFrom-Json

  foreach ($user in $users) {
    $externalUserObject = m365 spo externaluser list --siteUrl $site.url -o json --query "[?AcceptedAs == '$($user.Email)']" | ConvertFrom-Json

    $results += [pscustomobject][ordered]@{
      UserPrincipalName = $user.UserPrincipalName
      Email             = $user.Email
      InvitedAs         = $externalUserObject.InvitedAs
      WhenCreated       = $externalUserObject.WhenCreated
      InvitedBy         = $externalUserObject.InvitedBy
      Url               = $site.Url
    }
  }
}

Write-Host "Exporting file to $fileExportPath..."
$results | Export-Csv -Path $fileExportPath -NoTypeInformation
Write-Host "Completed."