SharePoint Online: PowerShell to Check If User Exists

Requirement: SharePoint Online PowerShell to check if user exists

There are different cases where you may need to check if a user exists in the Office 365 tenant and here is my PowerShell scripts:

Option 1: Check If User Exists in the Tenant using Azure AD Cmdlet
We can use the Get-MsolUser cmdlet of Azure AD to check if a given user account is valid.

Import-Module MSOnline

#User Account Variable
$UserAccount = "Salaudeen@crescent.com"

Try {
    #Get Credentials to connect
    $Cred = Get-Credential
 
    #Connect to Azure AD
    Connect-MsolService -Credential $Cred

    #Function to check if a user account exists in the tenant
    Function Check-UserExists()
    {
        Param( [Parameter(Mandatory=$true)] [string]$UserID )
     
        $User = Get-Msoluser -UserPrincipalName $UserID -Erroraction SilentlyContinue
        if ($User -ne $null)
        {
            Return $True
        }
        else
        {
            Return $False
        }
    }
    #Call the function to validate the user account
    Check-UserExists $UserAccount
}
Catch {    
    write-host -f Red "Error:" $_.Exception.Message
}

Option 2: SharePoint Online Ensure User method to Validate a user
Here is the native SharePoint method to validate a user using PowerShell: The "EnsureUser" method.

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

#Function to check if a user account is valid
Function Ensure-SPOUser()
{
    Param( 
        [Parameter(Mandatory=$true)] [string]$UserID,
        [Parameter(Mandatory=$true)] [string]$SiteURL
        )
    Try {
        #Setup Credentials to connect
        $Cred = Get-Credential

        #Setup the context
        $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
        $Ctx.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.UserName,$Cred.Password)
      
        #ensure sharepoint online user
        $Web = $Ctx.Web
        $User=$web.EnsureUser($UserID)
        $Ctx.ExecuteQuery()
        Return $True
    }
    Catch {    
        Return $False
    }
}

#Variables
$SiteURL = "https://crescent.sharepoint.com/Sites/marketing"
$UserID = "Salaudeen@crescent.com"
  
#Call the function to Check if the user account is valid
Ensure-SPOUser -UserID $UserID -SiteURL $SiteURL