One of Microsoft Office’s most diabolical bugs is finally being fixed

Last month, Microsoft announced a doozy of a bug: just typing in Word, Outlook, or OneNote could crash the app. Microsoft is now finally publishing a fix that will solve the problem — it’s coming next week.

On August 15, Microsoft disclosed that a version mismatch in Microsoft 365’s Office apps could have catastrophic consequences. “After updating to Version 2407 Build 17830.20138 or higher, you find that Outlook, Word, or OneNote may unexpectedly close when typing or doing other authoring tasks such as spell check,” Microsoft had said.

Now, a few weeks later, Microsoft has finally diagnosed the problem. “The crash issue is caused due to version mismatch between Office 2016 proofing tools in coexistence with Office language packs (M365 apps for Enterprise),” reads Microsoft’s support note. “These proofing tools are probably old traces from previous installs or part of Office suite migration. Coexistence of Office 2016 side by side with M365 apps is not supported due to different installation technologies of same version.”

Microsoft’s fix is already available, but you’ll need to be a Microsoft 365 Insider to access it. The fixed build is available as Version 2409 (Build 18021.15000) in the Beta Channel or Version 2409 (Build 18025.20000) in the Current Channel Preview.

If you’re just an ordinary Office 365 user, though, you’ll see the fix come out next week as part of Version 2409 (Build 18025.20000)’s stable release. That patch is expected to roll out on September 24.

The patch addresses both older versions of proofing tools that were installed with Microsoft 365 Office as well as a situation where the language pack version was different than the main installer. If you can’t wait, the support page also includes a workaround which involves uninstalling and reinstalling the language pack.

Further reading: What you need to know about Microsoft 365