New Outlook VDI Support: Deployment notes for virtual desktops

IT administrators deploying the new Outlook for Windows in Virtual Desktop Infrastructure environments must account for differences from the classic Outlook setup. Microsoft has redesigned the new Outlook to work with VDI, but it relies on a cloud-based architecture that changes how profiles, cached data, and licensing are handled. This article covers the deployment prerequisites, configuration steps, and known limitations you need to manage before rolling out new Outlook to virtual desktops.

What the New Outlook VDI Architecture Changes

The new Outlook for Windows is a progressive web app built on the Microsoft 365 platform. Unlike classic Outlook, which stores data in local PST or OST files, the new Outlook syncs all mailbox data directly from Exchange Online through the Microsoft Graph API. This architectural change eliminates the need for OST files on the VDI host, which reduces storage overhead and profile size.

However, the new Outlook still requires local caching for offline access and performance. In a VDI environment, this cached data must be stored in a user-profile container that persists between sessions. If the container is missing or misconfigured, users will see a blank mailbox every time they log in.

Another critical change is licensing. The new Outlook in VDI requires each user to have a Microsoft 365 E3, E5, Business Premium, or equivalent license that includes Exchange Online. Shared computer activation is not supported for the new Outlook in VDI. Each user must activate Office individually during their session.

Supported VDI Platforms for New Outlook

Microsoft officially supports the new Outlook on Windows 10 and Windows 11 multi-session virtual desktops running in Azure Virtual Desktop. Windows 365 Cloud PCs also support the new Outlook. On-premises VDI solutions such as VMware Horizon or Citrix Virtual Apps and Desktops are supported as long as the underlying OS meets the minimum build requirements: Windows 10 version 22H2 or Windows 11 version 22H2 with the latest cumulative updates.

Prerequisites for Deploying New Outlook in VDI

Before you deploy the new Outlook to virtual desktops, verify that the following components are in place.

1. Install the correct Microsoft 365 Apps channel
   The new Outlook requires Microsoft 365 Apps for Enterprise version 2302 or later, running on Current Channel or Monthly Enterprise Channel. Semi-Annual Enterprise Channel is not supported. Run the Office Deployment Tool with the Channel attribute set to Current or MonthlyEnterprise.
2. Configure FSLogix Profile Containers
   FSLogix is the recommended solution for persisting Outlook data between VDI sessions. Create a Profile Container or Office Container that includes the folder %LocalAppData%\Microsoft\Outlook\NewOutlook. Without this container, the new Outlook will not retain the user’s account configuration or cached messages.
3. Enable the new Outlook toggle via Group Policy
   Open the Group Policy Management Console. Navigate to Computer Configuration > Administrative Templates > Microsoft Outlook 2016 > Outlook Options > Other. Set the policy “Enable new Outlook” to Enabled. This makes the new Outlook toggle available in the classic Outlook client. If you want to skip the toggle and force new Outlook, set the policy to Enabled and also configure the registry key HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences\NewOutlookMigrationUserSetting to a DWORD value of 1.
4. Configure network endpoints for the new Outlook
   The new Outlook communicates with Exchange Online, Microsoft Graph, and Microsoft 365 services. Ensure the VDI hosts can reach the endpoints listed in Microsoft 365 URLs and IP address ranges. Specifically, allow traffic to outlook.office365.com, outlook.office.com, graph.microsoft.com, and all subdomains of office.com and live.com.
5. Assign the correct Microsoft 365 license
   Each user who signs into the new Outlook on a VDI session must have an Exchange Online license assigned. Shared computer activation is not supported. Use the Microsoft 365 admin center to verify that every target user has a valid license with the Exchange Online service plan enabled.

Configuration Steps for the New Outlook in VDI

After meeting the prerequisites, follow these steps to configure the new Outlook for your VDI users.

1. Create a golden image with the new Outlook pre-installed
   On a reference VDI machine, install Microsoft 365 Apps for Enterprise with the Current Channel. During installation, include the new Outlook component by adding is not used — instead, ensure Outlook is included. After installation, launch the new Outlook once to generate the initial folder structure. Then sysprep the machine and capture the image.
2. Apply Group Policy settings for VDI-specific behavior
   Set the following policies under Computer Configuration > Administrative Templates > Microsoft Outlook 2016:
   – Disable the “Turn off the new Outlook” policy to prevent users from switching back to classic Outlook.
   – Enable “Do not allow the new Outlook to be installed” if you want to block the new Outlook entirely — do not set this if you intend to use new Outlook.
   – Configure “Set the default mail client to the new Outlook” to make new Outlook the default handler for mailto links on the VDI.
3. Test with a small user group
   Assign the golden image to a test collection of 5-10 users. Have them sign in, open the new Outlook, and verify that their mailbox loads, they can send and receive mail, and their settings persist after they log off and log back on. Check the FSLogix logs at %ProgramData%\FSLogix\Logs for any errors related to the Outlook folder redirection.
4. Monitor performance with the Outlook Performance Monitor
   On the VDI host, open Performance Monitor and add the counter “Outlook” > “Sync Operations” and “Outlook” > “Latency”. A sync operation count above 50 per minute or latency above 500 ms indicates network or server-side issues. Adjust the VDI host’s network bandwidth or increase the number of Exchange Online licenses if needed.

If the New Outlook Fails to Load or Sync in VDI

New Outlook shows “Something went wrong” on sign-in

This error typically occurs when the user’s Microsoft 365 license is missing the Exchange Online service plan or when the VDI host cannot reach the Microsoft 365 authentication endpoints. Verify the license assignment in the Microsoft 365 admin center. Then test network connectivity from the VDI host to login.microsoftonline.com and outlook.office.com. If the host uses a proxy, ensure the proxy allows HTTP/2 traffic to these domains.

User settings and cached mail disappear after logoff

This indicates that the FSLogix Profile Container is not capturing the NewOutlook folder. Open the FSLogix configuration XML file located at %ProgramFiles%\FSLogix\Apps\frx.json or the Group Policy settings. Add the folder %LocalAppData%\Microsoft\Outlook\NewOutlook to the Include list. Then trigger a profile refresh by having the user log off and log back on.

New Outlook toggle is missing in classic Outlook

The toggle will not appear if the “Enable new Outlook” Group Policy is not applied or if the classic Outlook version is older than 2302. Confirm that the policy is set to Enabled and that the Office version on the VDI host matches the required channel. Run winver on the VDI host to check the Windows build — it must be 10.0.22621 or later for Windows 11, or 10.0.19045 for Windows 10.

New Outlook VDI vs Classic Outlook VDI: Feature Comparison

Item	New Outlook in VDI	Classic Outlook in VDI
Data storage	Cloud-only via Microsoft Graph API; no OST files	Local OST file cached on the VHD or profile container
Offline access	Limited to recently synced items; full offline mode not available	Full offline mode with cached Exchange mode
Profile size	Smaller — typically under 500 MB per user	Large — can exceed 10 GB per user with OST and search index
Licensing	Requires per-user Microsoft 365 license with Exchange Online	Supports shared computer activation with per-device licensing
Group Policy support	Limited — only basic toggle and default client policies	Full — hundreds of policies for security, add-ins, and behavior
Third-party add-in compatibility	Only web add-ins (JavaScript/HTML) are supported	COM add-ins, VSTO add-ins, and web add-ins are supported

With the new Outlook in VDI, you gain a smaller profile footprint and faster initial sign-in. You lose offline depth and add-in breadth. Choose the version that matches your organization’s reliance on offline work and legacy add-ins.

After you deploy the new Outlook to your virtual desktops, monitor the FSLogix container size weekly. A container that grows beyond 2 GB may indicate that the new Outlook is caching more data than expected. In that case, use the Group Policy setting “New Outlook cache size limit” to cap the local cache at 1 GB. This keeps logon and logoff times under 30 seconds.