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Exchange Server 2019 CU14 Exchange Server 2019 CU14 ESU only Hotfix update

KB5057652

KB5057652: Hotfix update for Exchange Server 2019 CU14, May 2025. Azure RMS transport failures and quarantined mailboxes addressed

In short

This hotfix fixes OWA calendar printing, journal-message conversion errors, StoreWorker failures that can quarantine mailboxes, and Edge Transport crashes when decrypting externally sent Azure RMS-protected messages. It also retires OWA access to Exchange Online archives for people with on-premises primary mailboxes.

Does it affect you? Applies to: Exchange Server 2019 CU14 x64 servers at organizations enrolled in the Extended Security Update program. This hotfix is HU5, build 15.2.1544.27.

Build
15.2.1544.27
Servicing branch
CU14
Review notes Additional details from the official release notes (2) Read notes
  • In short Exchange Online is retiring a feature that previously let people with an on-premises primary mailbox access their Exchange Online archive through OWA. The KB does not say this hotfix implements that retirement.
  • What changes Exchange Online is retiring a feature that previously let people with an on-premises primary mailbox access their Exchange Online archive through OWA. The KB does not say this hotfix implements that retirement.

The official sources are linked at the end of the page.

For servers running Cumulative Update 14: each cumulative update gets its own update. Support for this version ended on October 14, 2025: Microsoft releases this update only to organizations enrolled in the Extended Security Update (ESU) program, not through Microsoft Update. The others should move to Exchange Server Subscription Edition. Which version am I on?

What changes

Fixes 4 changes

Journal messages

  • Journal messages no longer get stuck in the submission queue with a ConversionFailedException.1
    The error is reported as 550 5.6.0 M2MCVT.StorageError.Exception: ConversionFailedException, Content conversion.

Calendar printing in OWA

For: Exchange administrators and OWA users

  • Printing a calendar from OWA works again instead of producing no print job on screen.2
    The issue occurs when you select Print in the OWA calendar print window.

Edge Transport service

  • The Edge Transport service no longer stops responding and restarting when Exchange Server decrypts externally sent messages protected by Azure Rights Management (Azure RMS).3
    The affected messages might be sent to the poison message queue, with Application event ID 10003 logged by MSExchangeTransport.

StoreWorker

  • StoreWorker no longer stops responding in the issue that can cause mailboxes to be quarantined.4
    The issue is associated with BaseViewOperatorDefinition and an MSExchangeIS event with ID 1002.

Removal 1 change

OWA access to Exchange Online archive mailboxes

For: Users with an on-premises primary mailbox and an Exchange Online archive

  • OWA access to an Exchange Online archive mailbox is being retired for people whose primary mailbox is hosted on-premises.5

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2025-05-29
Classification
Updates
Type
Cumulative update
Servicing branch
CU14
Replaces
KB5050673, KB5037224
Replaced by
KB5063222
VersionBuildChannel
2019 15.2.1544.27 General availability

Security

No vulnerabilities are listed for this update.

Sources

Updated
Cited passages from Microsoft's official notes (5)
  1. 1. Journal message returns "ConversionFailedException" support.microsoft.com
  2. 2. In this scenario, no print job appears on screen. support.microsoft.com
  3. 3. This issue occurs if Exchanger Server tries to decrypt messages that are sent from an external source that's protected by Azure Rights Management (Azure RMS). support.microsoft.com
  4. 4. The StoreWorker process stops responding in Microsoft Exchange Server 2019 or 2016. When this issue occurs, the mailboxes get quarantined support.microsoft.com
  5. 5. We are retiring a feature in Exchange Online that previously enabled who have a primary mailbox that's hosted on Exchange Server (on-premises) support.microsoft.com
Checked automatically: 8 of 8 checks passed, 5 quoted passages · compared with Microsoft's page on Oct 20, 2026
  • Quotes found in the official pages: passed
  • Numbers found in the sources: passed
  • Vulnerabilities from the dossier only: passed
  • Links to allowed domains only: passed
  • Every official change covered: passed
  • Readable plain text: passed
  • Changes confirmed by the file list: passed
  • Sources agree: passed

A second AI read the text against the sources: correctness 3/5, clarity 4/5, completeness 5/5. How we work

Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake