This guide installs a single Exchange Server 2019 Mailbox server in an Active Directory domain and licenses it with a Standard or Enterprise product key. It follows Microsoft's documented order: prerequisites, Active Directory preparation, setup, then licensing and verification. Before you start, read the support note below, because Exchange 2019 is past its end-of-support date in October 2026.
Is it still safe to install Exchange Server 2019?
Exchange Server 2019 reached the end of extended support on 14 October 2025, and Microsoft's paid Extended Security Update programme for it ends in October 2026, so a new installation suits labs, additional servers in an existing Exchange 2019 organisation or a short-term bridge, rather than a long-term internet-facing production mail system.
Microsoft's successor is Exchange Server Subscription Edition (SE), which installs like a cumulative update on Exchange 2019 CU14 or CU15 but needs an active subscription entitlement. Our Exchange 2019 Standard vs Enterprise guide explains editions, CALs and the SE position in more detail.
If you go ahead, install the latest cumulative update, CU15. Microsoft states that each Exchange 2019 CU is a full installation, so you do not need the original RTM release or earlier CUs first.
What are the prerequisites for Exchange Server 2019?
Exchange Server 2019 needs a domain-joined server running Windows Server 2019, 2022 or 2025 (Standard or Datacenter), a supported .NET Framework version, the Visual C++ 2012 and 2013 runtimes, Unified Communications Managed API (UCMA) 4.0, the IIS URL Rewrite module and the Server Media Foundation feature, all installed before setup runs.
Microsoft's Exchange Server prerequisites page and supportability matrix set the details:
- .NET Framework: 4.8.1 (recommended) or 4.8 on Windows Server 2022 or 2025; 4.8 only on Windows Server 2019.
- Runtimes: Visual C++ Redistributable for Visual Studio 2012 and for Visual Studio 2013.
-
UCMA 4.0: available in the
UCMARedistfolder on the Exchange media. - IIS URL Rewrite Module, downloaded from the IIS website.
-
Windows features:
Install-WindowsFeature Server-Media-Foundation, plus the IIS, .NET and clustering features, which setup can add for you. - Active Directory: forest functional level Windows Server 2012 R2 or higher, and the Remote Registry service set to Automatic.
Microsoft recommends 128 GB of memory for a Mailbox server. Server Core is supported and recommended; Desktop Experience also works, but in-place upgrades of the Windows Server version underneath Exchange are not supported, so choose the operating system carefully. Our Windows Server licence keys cover each supported version.
How do you prepare Active Directory for Exchange 2019?
You prepare Active Directory by running Exchange Setup three times from a command prompt with the licence-terms switch: first with /PrepareSchema to extend the schema, then /PrepareAD to create the Exchange organisation, and finally /PrepareAllDomains, using an account that is a member of the Schema Admins and Enterprise Admins groups.
Mount the Exchange ISO (in this example as drive E:) and run:
E:\Setup.exe /IAcceptExchangeServerLicenseTerms_DiagnosticDataOFF /PrepareSchemaE:\Setup.exe /IAcceptExchangeServerLicenseTerms_DiagnosticDataOFF /PrepareAD /OrganizationName:"Your Organisation"E:\Setup.exe /IAcceptExchangeServerLicenseTerms_DiagnosticDataOFF /PrepareAllDomains
Use _DiagnosticDataON instead if you want to send diagnostic data to Microsoft. The older /IAcceptExchangeServerLicenseTerms switch stopped working with the September 2021 cumulative updates, so scripts copied from older articles fail with it.
Two advanced points from Microsoft's Active Directory preparation guide: the organisation name cannot be changed later, and if a Windows Server 2025 domain controller holds the Schema Master role, install the November 2025 or later Exchange update before any PrepareAD step. Allow time for AD replication between steps in a multi-site forest.
How do you install the Exchange 2019 Mailbox role?
To install the Mailbox role, mount the Exchange 2019 CU15 ISO on the target server, run Setup.exe, accept the licence agreement, select Mailbox role with the option to install required Windows features automatically, pass the readiness checks, then click Install and restart the server when setup reports that it has completed.
- Right-click the ISO and select Mount, then run Setup.exe.
- Choose whether to check for updates, then click Next through the file copy and introduction pages.
- Accept the License Agreement and choose your Recommended Settings option.
- On Server Role Selection, tick Mailbox role and Automatically install Windows Server roles and features that are required to install Exchange.
- Accept or change the install path (default
C:\Program Files\Microsoft\Exchange Server\V15). - Choose the malware protection setting, fix any Readiness Checks errors, then click Install.
- When setup completes, click Finish and restart the server.
For scripted installs, Microsoft documents the unattended form: Setup.exe /IAcceptExchangeServerLicenseTerms_DiagnosticDataOFF /Mode:Install /Roles:Mailbox. The automatic Windows features option installs only Windows features; the .NET, Visual C++, UCMA and URL Rewrite prerequisites must already be present.
What we commonly see: readiness checks failing on a missing Visual C++ 2012 runtime or URL Rewrite module. Install the missing item and click Retry; Microsoft notes that restarting the server during the readiness checks means starting setup again from the beginning.
How do you enter the Exchange 2019 product key?
You enter the Exchange 2019 product key after installation, either in the Exchange admin center under Servers by editing the server and typing the key on the General tab, or in the Exchange Management Shell with Set-ExchangeServer and the -ProductKey parameter, then restart the Microsoft Exchange Information Store service.
In the Exchange admin center (EAC):
- Open
https://localhost/ecpon the Exchange server and sign in as an administrator. - Go to Servers > Servers, select the server and click Edit (or Enter Product Key in the details pane).
- On the General tab, enter the key in Enter a valid product key and click Save.
In the Exchange Management Shell:
- Run
Set-ExchangeServer EX01 -ProductKey XXXXX-XXXXX-XXXXX-XXXXX-XXXXX, replacing EX01 with your server name. - Run
Restart-Service MSExchangeISto restart the Information Store.
Cause and effect: the key sets the edition, so a Standard key limits that server to five mounted databases and an Enterprise key to 100. Microsoft's product key article confirms you can later move Standard to Enterprise with a key, but not the reverse without reinstalling. Licences: Exchange Server 2019 Standard or Exchange Server 2019 Enterprise.
How do you check that Exchange 2019 is licensed?
To check that Exchange 2019 is licensed, run Get-ExchangeServer with the server name and format the Name, Edition and trial properties, or open Servers in the Exchange admin center; a licensed server shows Standard or Enterprise as its edition and no longer reports itself as a trial edition.
-
One server:
Get-ExchangeServer EX01 | Format-List Name,Edition,*Trial* -
All servers:
Get-ExchangeServer | Format-Table -Auto Name,Edition,*Trial*
If something looks wrong, read the setup log at C:\ExchangeSetupLogs\ExchangeSetup.log and the Windows Application log. Without a key, Exchange runs as the Trial edition, which Microsoft says can be used for up to 180 days.
After licensing, the usual post-installation tasks are configuring virtual directory URLs, installing a trusted TLS certificate, creating send connectors and accepted domains, and adding Exchange CALs for every user or device. CAL rules are covered in the Standard vs Enterprise guide linked above.
Frequently asked questions
Can I enter the Exchange product key during setup?
Microsoft's documented process licenses the server after installation, through the Exchange admin center or the Set-ExchangeServer cmdlet, and Microsoft's unattended setup switch list does not include a product key switch. Install first, enter the key afterwards, then restart the Microsoft Exchange Information Store service.
Which Windows Server version should I use for Exchange 2019?
Exchange 2019 CU15 supports Windows Server 2019, 2022 and 2025 in Standard or Datacenter editions. Microsoft recommends .NET Framework 4.8.1 on 2022 or 2025, while 2019 supports .NET 4.8 only. Choose carefully, because upgrading the operating system in place underneath Exchange is not supported.
Do I need to download Exchange 2019 RTM before CU15?
No. Microsoft states that each Exchange 2019 cumulative update is a full installation that includes all earlier changes. Install a new server directly from the CU15 media, and run Active Directory preparation from the same media so the schema matches that update level.
Why does Setup fail with an IAcceptExchangeServerLicenseTerms error?
Since the September 2021 cumulative updates, the plain /IAcceptExchangeServerLicenseTerms switch no longer works. Use /IAcceptExchangeServerLicenseTerms_DiagnosticDataON or /IAcceptExchangeServerLicenseTerms_DiagnosticDataOFF instead, depending on whether you want to send diagnostic data to Microsoft. Use the same switch in every PrepareSchema, PrepareAD, PrepareAllDomains and install command, including any older scripts you reuse.
What happens if I never enter a product key?
The server stays licensed as the Trial edition. Microsoft says the trial can be used for up to 180 days and that no functionality is removed after it expires, but production use still requires a valid Standard or Enterprise licence. Enter the key in the EAC or Shell when ready.