EXCHANGE   Exchange 2013 – Cumulative Update 21 released



In June 2018 Microsoft released Cumulative Update 21 (build 15.00.1395.004) which is the last planned quarterly update for Exchange 2013 (https://blogs.technet.microsoft.com/rmilne/2018/06/19/exchange-2013-cu21-released/)

I was not sure about updating my Exchange 2013 directly from CU12 to CU21. It is supposed to be supported by Microsoft. Maybe I could install an intermediate CU before but, anyway, I decided to move on.

For this update it is necessary to install previously:
– .NET Framework 4.7.1
– Visual C++ Redistributable Packages for Visual Studio 2013

This document does not cover the procedure to update a DAG cluster or the role upgrading order. Simply the prerrequisites and the CU installation itself.

Install .Net Framework 4.7.1

Use the msu installer you can download here: https://www.catalog.update.microsoft.com/Search.aspx?q=KB4033369

In this post (Windows – .NET Framework 4.7.1 install stuck / hangs) I explain the problems I faced when trying to install it using the standard installer.

Windows - .NET Framework 4.7.1 install stuck hangsWindows - .NET Framework 4.7.1 msu packages install succesfully

Install VC++ 2013 runtime

Download from https://www.microsoft.com/en-us/download/details.aspx?id=40784 and install itMicrosoft Visual C++ 2013 installation

Download Exchange 2013 CU21

You can download it from: https://www.microsoft.com/en-us/download/details.aspx?id=57069

Update Active Directory Schema

I prefer to run this using a command and, if everything went ok, run the setup.
(Ensure you are running a user with member of “Domain Admins” and “Organization Management” groups.)

Run the CU21 setup.exe with the following parameters:

C:\soft\Update CU21>setup.exe /prepareAD /IAcceptExchangeServerLicenseTerms

Microsoft Exchange Server 2013 Cumulative Update 21 Unattended Setup

Copying Files...
File copy complete. Setup will now collect additional information needed for installation.

Performing Microsoft Exchange Server Prerequisite Check

Prerequisite Analysis                                             COMPLETED

Configuring Microsoft Exchange Server

Organization Preparation                                          COMPLETED

The Exchange Server setup operation completed successfully.

Install CU21

Now the schema is updated you can simply execute the setup.exe and follow the instructions.Exchange 2013 - Update CU21

In case you receive this error in the readiness check: “All Unified Messaging language packs other than US English (en-US) must be uninstalled before you can upgrade the Mailbox server role. Detected language packs: es-ES”…

Exchange 2013 - Update CU21 - Error unified messaging language packs must be uninstalled

Execute the following command for each language you have installed (the error message shows them):


C:\soft\Update CU21>setup.exe /RemoveUmLanguagePack:es-ES

Microsoft Exchange Server 2013 Cumulative Update 21 Unattended Setup

Copying Files...
File copy complete. Setup will now collect additional information needed for installation.
UM Language Pack for es-ES

Performing Microsoft Exchange Server Prerequisite Check


Configuring Microsoft Exchange Server

UM language pack for (es-ES)                                     COMPLETED

The Exchange Server setup operation completed successfully.

And rerun the setup:Exchange 2013 - Update CU21 - Error unified messaging language packs must be uninstalled

Exchange 2013 - Update CU21

Exchange 2013 - Update CU21

2 thoughts on “Exchange 2013 – Cumulative Update 21 released

  1. Recently installed CU 21 but shared parameter is not available because missed to manually run /prepareAD command. So will it fine now to run /prepare AD command post installation of CU . Can you please help

    • I prefer to run /prepareAD manually but is not mandatory.
      If you run the CU normally, the active directory schema is also supposed to be updated.
      And furthermore, the schema has not changed since CU10 so probably you dont have any problem.
      Anyway, if you want to check your schema version, you can run the following dsquery (modify dc=yourdomain,dc=com for your domain):

      dsquery * CN=ms-Exch-Schema-Version-Pt,cn=schema,cn=configuration,dc=yourdomain,dc=com -scope base -attr rangeUpper

      The rangeUpper version should be 15312

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