Sign in with Microsoft
Sign in or create an account.
Select a different account.
You have multiple accounts
Choose the account you want to sign in with.

Important: This regularly scheduled cumulative update contains all the security fixes of the security updates in June and other previous security updates..

Known issues in this cumulative update

  • In multidomain Active Directory forests in which Exchange is installed or was prepared previously by using the /PrepareDomain option in Setup, this action must be completed after the /PrepareAD command for this cumulative update has been completed and the changes are replicated to all domains. Setup will try to run the /PrepareAD command during the first server installation. Installation will finish only if the user who initiated Setup has the appropriate permissions.

    • About the /PrepareDomain operation in multidomain:

      The /PrepareDomain operation automatically runs in the Active Directory domain in which the /PrepareAD command is run. However, it may be unable to update other domains in the forest. Therefore, a domain administrator should run the /PrepareDomain in other domains in the forest.

    • About the permission question:

      Because /PrepareAD is triggered in Setup, if the user who initiates Setup isn't a member of Schema Admins and Enterprise Admins, the readiness check will fail and you receive the following error messages.

      Error 1:

      The Active Directory schema isn't up-to-date, and this user account isn't a member of the 'Schema Admins' and/or 'Enterprise Admins' groups. For more informaion, visit:

      Error 2:

      Global updates need to be made to Active Directory, and this user account isn't a member of the 'Enterprise Admins'group. For more information, visit:

  • Autodiscover Event ID 1 occurs after you install Cumulative Update 3 for Exchange Server 2019. For more information, see KB 4532190.

  • "500 Unexpected Error" when trying to create a user mailbox in ECP. For more information, see KB 5001874.

  • "Cannot Send Mail - Your mailbox is full" error when you use iPhone mail to send very large attachments. For more information, see KB 5004622.

Issues that this cumulative update fixes

This cumulative update also fixes the issues that are described in the following Microsoft Knowledge Base articles:

  • 5004612 Message body not displayed in OWA if the message was added in Outlook to a new mailbox

  • 5004613 OutOfMemory exception when moving a public folder that has a large ICS sync state

  • 5004614 Korean text is garbled in calendar invitation to a user with a Chinese display name

  • 5004615 "InvalidOperationException" and Store Worker process crashes during mailbox move

  • 5004616 Changing the email address in EAC doesn't work in modern browsers

  • 5004617 TLS 1.2 is not set as default after you install Exchange 2019 with Edge Transport role

  • 5004618 MSExchangeMailboxAssistants 4999 Crash in ELCAssistant.InvokeInternalAssistant with System.NullReferenceException

  • 5004619 Mailbox creation through ECP fails after installing Exchange Server 2019 or 2016 April update

Get Cumulative Update 10 for Exchange Server 2019

Volume Licensing Center

To get Cumulative Update 10 for Exchange Server 2019, go to Microsoft Volume Licensing Center.

Note The Cumulative Update 10 package can be used to run a new installation of Exchange Server 2019 or to upgrade an existing Exchange Server 2019 installation to Cumulative Update 10.

File information

File hash information

File name

SHA256 hash



Change history

 The following table summarizes some of the most important changes to this topic.



August 30, 2021

Added a "New feature in this cumulative update" section.

Need more help?

Want more options?

Explore subscription benefits, browse training courses, learn how to secure your device, and more.

Communities help you ask and answer questions, give feedback, and hear from experts with rich knowledge.

Was this information helpful?

What affected your experience?
By pressing submit, your feedback will be used to improve Microsoft products and services. Your IT admin will be able to collect this data. Privacy Statement.

Thank you for your feedback!