[Urgent] Possibly Microsoft 365 Office Apps updates crashing my Word Addin

Question

Starting sometime around Nov 14, 2024, we have been observing consistent issues with our software product called Intelligent Content Tools (icTools) on some of our machines having Microsoft 365 installed. icTools is a plugin to Microsoft Word. This has critically impacted out software development process and likely to be impacting our customers as well who are using the product.

We have following observations based on our internal troubleshooting.

1. Word Crashes Upon Using icTools: Microsoft Word crashes on some machines while using certain functions of icTools. See this short video for the behavior.
2. Only Some Machines Having Latest Microsoft 365 Office update Run into Issues: We noticed that not all of our machines run into this issue which have Microsoft 365 as well as latest Office update (Version 2410, Build 18129.20158, Released on Nov 12) installed. AND THAT IS WIERD.
3. No Recent Windows Update Since Issue Started Happening on Machines: Issues have been observed on machines having Windows 10 and 11 where no recent Windows updates installed.
4. icTools Low-level Troubleshooting Shows Window Handle is Null: Debugging on affected machine at low-level found that icTools application is unable to get Window handle as it appears null. There is method bool GetWordHWNDs(word::Window *pWdWnd, WordHWNDs *pHwnds) that is returning handle value as null. Inside this method, there are some checks that check against the class name “_WwF” that are failing because the class name we are getting from Microsoft Word now is “_WwB” which is leading to the issue.

We are looking for your assistance in resolving this issue at the earliest.

Answer 1

Here are some quick steps to troubleshoot the issue:Here are some quick steps to troubleshoot the issue, hope it helps:

1. Update Office: Ensure all machines have the latest Microsoft 365 updates.
2. Repair Office: Use the repair option in Control Panel or Settings.
3. Disable Add-ins: Turn off all add-ins except icTools to check for conflicts.
4. Safe Mode: Run Word in Safe Mode by holding Ctrl while starting Word.
5. Check Code: Update your GetWordHWNDs method to handle both “_WwF” and “_WwB” class names.
6. Rollback Update: Consider rolling back to a previous Office version if the issue started after the latest update.

Answer 2

Seems like Microsoft has pushed some updates few mins ago, windows handle nesting is back as normal (OpusApp ->_WwF ->_WwB), so we are good now.
Thank you @Kilian and @dirvo for your response and off course MS developer team.