List all users' last login date

JakobRohde this is a classic Microsoft 365 housekeeping task and question. A pity Microsoft is not offering something out of the box.

I would suggest following Powershell script, which returns not only your users last login date as CSV file, but also assigned licenses. This way you may check whether there is someone not logging in and consuming licenses.

Install-Module AzureADPreview -AllowClobber -Force

Connect-AzureAD

$usersexport = [system.collections.arraylist]@()

Get-AzureADUser | % {
    $User = $_
    $UPN = $User.UserPrincipalName
    
    Write-Output "Start analysing $UPN"

    $LoginTime = Get-AzureAdAuditSigninLogs -top 1 -filter "userprincipalname eq '$UPN'" | select CreatedDateTime
    $Licenses = Get-AzureADUserLicenseDetail -ObjectId $User.ObjectId | % { $_.ServicePlans | Where {$_.AppliesTo -eq "User"}} | select -ExpandProperty ServicePlanName
    
    $Export = [pscustomobject]@{
        'DisplayName' = $User.DisplayName; 
        'UserPrincipalName' = $UPN;
        'LastSignInDate' = $LoginTime.CreatedDateTime;
        'Licenses' = $Licenses -join ",";
    }
    
    $usersexport.Add($Export)
    
    Write-Output $Export
}
$usersexport | Export-CSV $Home\LastLogonDate.csv

No. Use the report in the O365 admin center -> Reports -> Usage -> Active users.

This might give you what you're after...

https://community.spiceworks.com/scripts/show/2290-last-log-in-time-and-date-powershell-script-for-office-365-to-desktop-csv-file

Once you've logged in and authenticated against your Office 365 tenant, you can then use the below commands.

# Connects you to Windows Azure Active Directory

Connect-MsolService

# Gets Unlicenced users and lists the "DisplayName, LastLogonTime and LastLogoffTime"

Get-MsolUser -UnlicensedUsersOnly | Foreach {Get-MailboxStatistics $_.UserPrincipalName | Select DisplayName, LastLogonTime, LastLogoffTime}

JakobRohde VasilMichev 

The Microsoft Graph API now supports the resource property signInActivity in users end-point, this resource exposes the lastSignInDateTime property which shows the last time a user made a successful sign-in. Fetching signInActivity property requires an Azure AD Premium P1/P2 license and the AuditLog.Read.All permission. The following request retrieves user details along with signInActivity property.

#GET Request
https://graph.microsoft.com/beta/users?$select=displayName,signInActivity

Before Microsoft Graph supports this property, we need to either get the mailbox last logon time using the Get-MailboxStatistics cmdlet or we need to crawl the Azure AD sign-in logs or the Unified audit logs in the Security and Compliance Center. 

You can refer the below post to know more details about how to find and export Last login date for all Azure AD Users using PowerShell.

• https://morgantechspace.com/2021/09/find-last-login-date-for-all-azure-ad-users-using-powershell.html

JakobRohde 

This can be done using AzureADPreview

Import-Module AzureADPreview
$UsersUPN = (Get-AzureADUser -Top 20000).UserPrincipalName

foreach($user in $UsersUPN)
    {
        Get-AzureADAuditSignInLogs -Filter "UserPrincipalName eq '$user'" -Top 1| `
        select CreatedDateTime, UserPrincipalName, IsInteractive, AppDisplayName, IpAddress, TokenIssuerType, @{Name = 'DeviceOS'; Expression = {$_.DeviceDetail.OperatingSystem}}
        Start-Sleep -Seconds 5
    }

 A Start-Sleep -Seconds 5 delay should be added in order to bypass the "Too many requests" error code