Word: crash during mail merge with .dot/.dotm templates after version 2603
Summary
Word for Microsoft 365 can crash when performing a mail merge with templates (.dot/.dotm) after updating to version 2603 (build 19822.20180). Microsoft has confirmed the issue. The Word team is investigating and no workaround or fix is published yet.
Symptoms
Word crashes when a mail merge is performed with a .dot or .dotm template file.
Affected
- Word for Microsoft 365
- Version 2603 (build 19822.20180)
- Mail merge with .dot/.dotm templates
Workaround
No workaround known.
Fix
Not fixed yet. Status at Microsoft: investigating (last updated April 29, 2026).
Recommendation
Check whether mail merges with .dot/.dotm templates are used in your business. If so, avoid updating those users to version 2603 until a fix is available, or test the mail merge first. Monitor the Microsoft known-issues page for updates.
Sources
- Word: Word might crash when performing a mail merge with templates (.dot/dotm) Vendor · support.microsoft.com
Compiled from the sources listed and translated with AI (Claude); status and dates come from the vendor. The vendor’s statements are authoritative. Updated 1 Nov 2026, 18:20.
Where the information comes from
We continuously read the vendors’ official sources, community reports and trade media and summarise them in our own words, with a link to the source:
- Microsoft: Windows release health (Windows 10/11, Server 2016 to 2025), Windows message center, known issues of Microsoft 365 Apps (Outlook, Excel, Word, PowerPoint), Edge, Intune, Autopilot, Windows 365 and Entra Connect, Microsoft KB articles with timelines, Exchange and Windows IT Pro blogs, optionally Microsoft 365 service health and message center
- other vendors: Veeam KB, Citrix (known issues), Ubuntu and Debian (regressions), Broadcom (VMware), Fortinet, Cisco, Mozilla, Let’s Encrypt
- community (title, short excerpt and link only, without the names of the authors): Microsoft Q&A, Microsoft Tech Community (discussions), Veeam R&D Forums, Eleven Forum
- targeted web research with AI (Claude), e.g. on the updates of the month – this also finds discussions on Reddit and in forums; such entries are labelled as community reports until the vendor confirms them
- early warning from trade media (title and link only): Born’s Tech and Windows World, BleepingComputer, AskWoody, Windows Latest, Windows Central, gHacks, The Windows Club, Deskmodder, Dr. Windows, WindowsArea, Frankys Web, heise online
Summary and translation with AI (Claude by Anthropic) – without any data of visitors.
Affected? We can help.
We check whether your systems are affected, apply workarounds properly and plan for dated changes in good time.