Get-InactiveUsers.ps1

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<#
	.SYNOPSIS
		Get users via Microsoft Graph based on lack of sign-in activity

	.DESCRIPTION
        This script will retrieve a list of users who have not signed in for at least a specified number of days.
        Requires Microsoft Entra P1 or P2 license in the tenant.
        Requires the signed in user to have User.Read.All (or higher) delegated scope.
            Permissions: https://learn.microsoft.com/en-us/graph/api/user-list?view=graph-rest-1.0&tabs=http#permissions
        Requires the signed in user to have AuditLog.Read.All delegated scope and a sufficient Entra role. (Reports Reader is least privileged role.)
            Permissions: https://learn.microsoft.com/en-us/graph/api/signin-list?view=graph-rest-1.0&tabs=http#permissions

    .PARAMETER SignInType
        Filter users on the type of sign-in: interactive (successful or unsuccessful), non-interactive (successful or unsuccessful),
        or successful (for either type). Valid values are Interactive, NonInteractive, and Successful.
        Successful is the default.

    .PARAMETER MemberDaysOfInactivity
        The number of days of sign-in inactivity for a member user to be returned. Default value is 30.
        Note: Users with a null value for the date/time of the sign-in type will not be returned.

    .PARAMETER GuestDaysOfInactivity
        The number of days of sign-in inactivity for a guest user to be returned. Default value is 90.
        Cannot be less than MemberDaysOfInactivity if members are included.
        Note: Users with a null value for the date/time of the sign-in type will not be returned.
    
    .PARAMETER CloudEnvironment
        Cloud instance of the tenant. Possible values are Commercial, USGovGCC, USGovGCCHigh, USGovDoD, and China.
        Default value is Commercial.

    .PARAMETER UserType
        Filter users based on their type. Valid values are Member and Guest. Default is both.

    .PARAMETER DoNotExportToCSV
        Switch to skip exporting the results to CSV and instead output the result objects to the host.
        
	.NOTES
        Version 1.5
        July 30, 2025

	.LINK
		about_functions_advanced   
#>
#Requires -Modules @{ModuleName = 'Microsoft.Graph.Authentication'; ModuleVersion = '2.0.0'}
[CmdletBinding()]
param (
    [ValidateSet('Interactive','NonInteractive','Successful')]$SignInType = 'Successful',
    [int]$MemberDaysOfInactivity = 30,
    [int]$GuestDaysOfInactivity = 90,
    [ValidateSet("Member", "Guest")][string[]]$UserType = @("Member", "Guest"),
    [ValidateSet("Commercial", "USGovGCC", "USGovGCCHigh", "USGovDoD", "China")][string]$CloudEnvironment="Commercial",
    [switch]$DoNotExportToCSV
)

if ($UserType -contains 'Member' -and $GuestDaysOfInactivity -lt $MemberDaysOfInactivity) {
    Write-Error -Message "GuestDaysOfInactivity cannot be less than MemberDaysOfInactivity when UserType includes Members."
    exit
}

# Start-Transcript -Path "Transcript-inactiveusers.txt" -Append
switch ($CloudEnvironment) {
    "Commercial"   {$cloud = "Global"}
    "USGovGCC"     {$cloud = "Global"}
    "USGovGCCHigh" {$cloud = "USGov"}
    "USGovDoD"     {$cloud = "USGovDoD"}
    "China"        {$cloud = "China"}            
}

if (-not(Get-MgContext)) {
    Write-Host -ForegroundColor Green "$(Get-Date) Connecting to Microsoft Graph..."
    Connect-MgGraph -ContextScope CurrentUser -Environment $cloud -NoWelcome
}

$neededScopes = @()
# Supported scope for Users API from least to most privileged
$supportedScopes = @('User.Read.All', 'User.ReadWrite.All', 'Directory.Read.All', 'Directory.ReadWrite.All')
foreach ($scope in (Get-MgContext).Scopes) {
    if ($scope -in $supportedScopes) {
        $userScopeInCurrentContext = $true
        break
    }
}
if ((-not($userScopeInCurrentContext))) {
    $neededScopes += 'User.Read.All'
}
# Supported scope for Sign-ins API
if ((Get-MgContext).Scopes -notcontains 'AuditLog.Read.All') {
    $neededScopes += 'AuditLog.Read.All'
}

if ($neededScopes) {
    Write-Host -ForegroundColor Green "$(Get-Date) Reconnecting to Microsoft Graph and requesting new scopes..."
    Connect-MgGraph -ContextScope CurrentUser -Scopes $neededScopes -Environment $cloud -NoWelcome
}

if ($UserType -contains 'Member') {
    $targetdate = (Get-Date).ToUniversalTime().AddDays(-$MemberDaysOfInactivity).ToString("o")
} else {
    $targetdate = (Get-Date).ToUniversalTime().AddDays(-$GuestDaysOfInactivity).ToString("o")
}
# Used for client-side filtering of results for guest users
$guestTargetDate = (Get-Date).ToUniversalTime().AddDays(-$GuestDaysOfInactivity)

$result = New-Object -TypeName System.Collections.ArrayList
switch ($SignInType) {
    Interactive {$siFilter = 'signInActivity/lastSignInDateTime'}
    NonInteractive {$siFilter = 'signInActivity/lastNonInteractiveSignInDateTime'}
    Successful {$siFilter = 'signInActivity/lastSuccessfulSignInDateTime'}
}

# Filtering on signInActivity cannot be used with any other filterable properties, so filtering on userType is performed client-side
# https://learn.microsoft.com/en-us/entra/identity/monitoring-health/howto-manage-inactive-user-accounts
$apiUrl = "/v1.0/users?`$filter=$siFilter lt $($targetdate)&`$select=accountEnabled,id,userType,signInActivity,userprincipalname"
Write-Verbose "Initial URL: $apiUrl"
$typeMessage = @()
if ($UserType -contains 'Member') {
    $typeMessage += "member users with $MemberDaysOfInactivity+ days"
}
if ($UserType -contains 'Guest') {
    $typeMessage += "guest users with $GuestDaysOfInactivity+ days"
}
Write-Host -ForegroundColor Green "$(Get-Date) Getting $($typeMessage -join ' and ') of sign-in inactivity..."
do {
    # Get data via Graph and continue paging until complete
    $response = Invoke-MgGraphRequest -Method GET $apiUrl -OutputType PSObject
    $apiUrl = $($response."@odata.nextLink")
    if ($apiUrl) { Write-Verbose "@odata.nextLink: $apiUrl" }
    $result.AddRange($response.value) | Out-Null
}
until ($null -eq $response."@odata.nextLink")

if ($result.Count -gt 0) {
    # Processing user data to prepare export
    #Write-Host -ForegroundColor Green "$(Get-Date) Processing $($result.Count) returned users..."

    $return=@()
    foreach ($item in $result) {
        if (($UserType -contains 'Member' -and $item.userType -eq 'Member') -or 
            ($UserType -contains 'Guest' -and $item.userType -eq 'Guest' -and $item.'signInActivity'.$($siFilter.SubString($siFilter.IndexOf('/')+1)) -lt $guestTargetDate)) {

            if ($null -ne $item.userPrincipalName -and $item.accountEnabled -eq $true) {
                $return += New-Object -TypeName PSObject -Property @{
                    UserPrincipalName = $item.userPrincipalName
                    LastSuccessfulSignIn = $item.signInActivity.lastSuccessfulSignInDateTime
                    LastInteractiveSignIn = $item.signInActivity.lastSignInDateTime
                    LastNonInteractiveSignIn = $item.signInActivity.lastNonInteractiveSignInDateTime
                    UserType = $item.userType
                }
            }
        }
    }

    if ($return.Count -gt 0) {
        # Export to CSV unless opted out
        if ($DoNotExportToCSV -eq $false) {
            Write-Host -ForegroundColor Green "$(Get-Date) Exporting EntraID-InactiveUsers.csv in current directory..."  
            $return | Select-Object -Property UserPrincipalName,UserType,LastSuccessfulSignIn,LastInteractiveSignIn,LastNonInteractiveSignIn | Export-CSV "EntraID-InactiveUsers.csv" -NoTypeInformation
        }

        if ($DoNotExportToCSV -eq $true) {
            $return
        }
    } else {
        Write-Host -ForegroundColor Green "$(Get-Date) No users match the search criteria."
    }
} else {
    Write-Host -ForegroundColor Green "$(Get-Date) No users were returned based on the search criteria."
}

Write-Host -ForegroundColor Green "$(Get-Date) Script has completed."
# Stop-Transcript