powershell-scripts/Get M365 Inactive User Report/GetM365InactiveUserReport.ps1

<#
=============================================================================================
Name:           Export Microsoft 365 Inactive Users Report using MS Graph PowerShell
Version:        1.0
website:        o365reports.com

Script Highlights:
~~~~~~~~~~~~~~~~~
1.The single script allows you to generate 10+ different inactive user reports.
2.The script can be executed with an MFA-enabled account too. 
3.The script supports Certificate-based authentication (CBA). 
4.Provides details about non-interactive sign-ins too. 
5.You can generate reports based on inactive days.
6.Helps to filter never logged-in users alone. 
7.Generates report for sign-in enabled users alone. 
8.Supports filteringlicensed users alone. 
9.Gets inactive external users report. 
10.Export results to CSV file. 
11.The assigned licenses column will show you the user-friendly-name like ‘Office 365 Enterprise E3’ rather than ‘ENTERPRISEPACK’. 
12.Automatically installs the MS Graph PowerShell module (if not installed already) upon your confirmation. 
13.The script is scheduler friendly.

For detailed Script execution:  https://o365reports.com/2023/06/21/microsoft-365-inactive-user-report-ms-graph-powershell
============================================================================================
#>

Param
(
    [int]$InactiveDays,
    [int]$InactiveDays_NonInteractive,
    [switch]$ReturnNeverLoggedInUser,
    [switch]$EnabledUsersOnly,
    [switch]$DisabledUsersOnly,
    [switch]$LicensedUsersOnly,
    [switch]$ExternalUsersOnly,
    [switch]$CreateSession,
    [string]$TenantId,
    [string]$ClientId,
    [string]$CertificateThumbprint
)

Function Connect_MgGraph
{
 #Check for module installation
 $Module=Get-Module -Name microsoft.graph -ListAvailable
 if($Module.count -eq 0) 
 { 
  Write-Host Microsoft Graph PowerShell SDK is not available  -ForegroundColor yellow  
  $Confirm= Read-Host Are you sure you want to install module? [Y] Yes [N] No 
  if($Confirm -match "[yY]") 
  { 
   Write-host "Installing Microsoft Graph PowerShell module..."
   Install-Module Microsoft.Graph -Repository PSGallery -Scope CurrentUser -AllowClobber -Force
  }
  else
  {
   Write-Host "Microsoft Graph PowerShell module is required to run this script. Please install module using Install-Module Microsoft.Graph cmdlet." 
   Exit
  }
 }
 #Disconnect Existing MgGraph session
 if($CreateSession.IsPresent)
 {
  Disconnect-MgGraph
 }

 #Connecting to MgGraph beta
 Select-MgProfile -Name beta
 Write-Host Connecting to Microsoft Graph...
 if(($TenantId -ne "") -and ($ClientId -ne "") -and ($CertificateThumbprint -ne ""))  
 {  
  Connect-MgGraph  -TenantId $TenantId -AppId $ClientId -CertificateThumbprint $CertificateThumbprint 
 }
 else
 {
  Connect-MgGraph -Scopes "User.Read.All","AuditLog.read.All"  
 }
}
Connect_MgGraph

$ExportCSV = ".\InactiveM365UserReport_$((Get-Date -format yyyy-MMM-dd-ddd` hh-mm-ss` tt).ToString()).csv"
$ExportResult=""   
$ExportResults=@()  

#Get friendly name of license plan from external file
$FriendlyNameHash=Get-Content -Raw -Path .\LicenseFriendlyName.txt -ErrorAction Stop | ConvertFrom-StringData

$Count=0
$PrintedUser=0
#retrieve users
$RequiredProperties=@('UserPrincipalName','EmployeeId','CreatedDateTime','AccountEnabled','Department','JobTitle','RefreshTokensValidFromDateTime','SigninActivity')
Get-MgUser -All -Property $RequiredProperties | select $RequiredProperties | ForEach-Object {
 $Count++
 $UPN=$_.UserPrincipalName
 Write-Progress -Activity "`n     Processing user: $Count - $UPN"
 $EmployeeId=$_.EmployeeId
 $LastInteractiveSignIn=$_.SignInActivity.LastSignInDateTime
 $LastNon_InteractiveSignIn=$_.SignInActivity.LastNonInteractiveSignInDateTime
 $CreatedDate=$_.CreatedDateTime
 $AccountEnabled=$_.AccountEnabled
 $Department=$_.Department
 $JobTitle=$_.JobTitle
 $RefreshTokenValidFrom=$_.RefreshTokensValidFromDateTime
 #Calculate Inactive days
 if($LastInteractiveSignIn -eq $null)
 {
  $LastInteractiveSignIn = "Never Logged In"
  $InactiveDays_InteractiveSignIn = "-"
 }
 else
 {
  $InactiveDays_InteractiveSignIn = (New-TimeSpan -Start $LastInteractiveSignIn).Days
 }
 if($LastNon_InteractiveSignIn -eq $null)
 {
  $LastNon_InteractiveSignIn = "Never Logged In"
  $InactiveDays_NonInteractiveSignIn = "-"
 }
 else
 {
  $InactiveDays_NonInteractiveSignIn = (New-TimeSpan -Start $LastNon_InteractiveSignIn).Days
 }
 if($AccountEnabled -eq $true)
 {
  $AccountStatus='Enabled'
 }
 else
 {
  $AccountStatus='Disabled'
 }

 #Get licenses assigned to mailboxes
 $Licenses = (Get-MgUserLicenseDetail -UserId $UPN).SkuPartNumber
 $AssignedLicense = @()

 #Convert license plan to friendly name
 if($Licenses.count -eq 0)
 {
  $LicenseDetails = "No License Assigned"
 }
 else
 {
  foreach($License in $Licenses)
  {
   $EasyName = $FriendlyNameHash[$License]
   if(!($EasyName))
   {$NamePrint = $License}
   else
   {$NamePrint = $EasyName}
   $AssignedLicense += $NamePrint
  }
  $LicenseDetails = $AssignedLicense -join ", "
 }
 $Print=1


 #Inactive days based on interactive signins filter
 if($InactiveDays_InteractiveSignIn -ne "-")
 {
  if(($InactiveDays -ne "") -and ($InactiveDays -gt $InactiveDays_InteractiveSignIn))
  {
   $Print=0
  }
 }
    
 #Inactive days based on non-interactive signins filter
 if($InactiveDays_NonInteractiveSignIn -ne "-")
 {
  if(($InactiveDays_NonInteractive -ne "") -and ($InactiveDays_NonInteractive -gt $InactiveDays_NonInteractiveSignIn))
  {
   $Print=0
  }
 }

 #Never Logged In user
 if(($ReturnNeverLoggedInUser.IsPresent) -and ($LastInteractiveSignIn -ne "Never Logged In"))
 {
  $Print=0
 }

 #Filter for external users
 if(($ExternalUsersOnly.IsPresent) -and ($UPN -notmatch '#EXT#'))
 {
   $Print=0
 }
 
 #Signin Allowed Users
 if($EnabledUsersOnly.IsPresent -and $AccountStatus -eq 'Disabled')
 {      
  $Print=0
 }

 #Signin disabled users
 if($DisabledUsersOnly.IsPresent -and $AccountStatus -eq 'Enabled')
 {
  $Print=0
 }

 #Licensed Users ony
 if($LicensedUsersOnly -and $Licenses.Count -eq 0)
 {
  $Print=0
 }

 #Export users to output file
 if($Print -eq 1)
 {
  $PrintedUser++
  $ExportResult=[PSCustomObject]@{'UPN'=$UPN;'Creation Date'=$CreatedDate;'Last Interactive SignIn Date'=$LastInteractiveSignIn;'Last Non Interactive SignIn Date'=$LastNon_InteractiveSignIn;'Inactive Days(Interactive SignIn)'=$InactiveDays_InteractiveSignIn;'Inactive Days(Non-Interactive Signin)'=$InactiveDays_NonInteractiveSignin;'Refresh Token Valid From'=$RefreshTokenValidFrom;'Emp id'=$EmployeeId;'License Details'=$LicenseDetails;'Account Status'=$AccountStatus;'Department'=$Department;'Job Title'=$JobTitle}
  $ExportResult | Export-Csv -Path $ExportCSV -Notype -Append
 }
}

#Open output file after execution
Write-Host `nScript executed successfully
if((Test-Path -Path $ExportCSV) -eq "True")
{
    Write-Host "Exported report has $PrintedUser user(s)" 
    $Prompt = New-Object -ComObject wscript.shell
    $UserInput = $Prompt.popup("Do you want to open output file?",` 0,"Open Output File",4)
    if ($UserInput -eq 6)
    {
        Invoke-Item "$ExportCSV"
    }
    Write-Host "Detailed report available in: $ExportCSV"
}
else
{
    Write-Host "No user found" -ForegroundColor Red
}