Update Mobile Numbers for Microsoft 365 Users via PowerShell

Purpose

This article explains how to update mobile numbers for multiple Microsoft 365 users using a PowerShell script. It also shows how to check update status (Success/Failed) directly in the PowerShell console.

Prerequisites

• Microsoft Graph PowerShell module installed

  Install-Module Microsoft.Graph -Scope AllUsers
  

• Administrator account with the following Microsoft Graph API permissions:

  • User.ReadWrite.All

  • Directory.ReadWrite.All

• A CSV file containing users and their new mobile numbers.

Example Mobile Number Update.csv:

UserPrincipalName,Mobile rohit@domain.com,+919876543210 kamal@domain.com,+918888888888

Steps to Run

1. Connect to Microsoft Graph

Open PowerShell as Administrator and run:

Disconnect-MgGraph Connect-MgGraph -Scopes "User.Read.All","User.ReadWrite.All","Directory.Read.All","Directory.ReadWrite.All" Select-MgProfile -Name beta

2. Save Script

Save the following script as Update-MobileNumbers.ps1:

# Input CSV path $csvPath = "C:\Users\<YourUser>\OneDrive\Desktop\Mobile Number Update.csv" 
# Process each user and show status in console only Import-Csv $csvPath | ForEach-Object {    try {        Update-MgUser -UserId $_.UserPrincipalName -MobilePhone $_.Mobile -ErrorAction Stop        Write-Host "✅ Success: $($_.UserPrincipalName) → $($_.Mobile)" -ForegroundColor Green    }    catch {        Write-Host "❌ Failed: $($_.UserPrincipalName) → $($_.Mobile)" -ForegroundColor Red        Write-Host "   Error: $($_.Exception.Message)" -ForegroundColor Yellow    } }

3. Run the Script

.\Update-MobileNumbers.ps1

Expected Output

• Success messages appear in green

• Failure messages appear in red

• Errors are displayed in yellow with details

Example:

✅ Success: rohit@domain.com → +919876543210
❌ Failed: kamal@domain.com → +918888888888   Error: Property is read-only for AD-synced users

Notes

• If a user is AD-synced (hybrid environment), the mobile number cannot be updated via Microsoft 365. You must update it in Active Directory and then run a sync.

• For cloud-only users, updates will apply immediately.