Intermittent Excel crashes with VBA and VSTO add-ins after Version 2608 update

Question

Intermittent Excel crashes with VBA and VSTO add-ins after Version 2608 update

Raiyan Ahmed 0

Hello,

Since the initial release of Microsoft 365 Apps Version 2608 around August 18, 2026, multiple users have experienced intermittent Excel crashes.

Affected environment:

Monthly Enterprise Channel Version 2608, Build 20326.20142
64-bit Excel on Windows 11
Both physical laptops and virtual desktops
VBA workbooks and files using the OneStream VSTO/COM add-in

Excel may crash while opening a workbook, running macros, refreshing, or submitting data. The same operation may later succeed without changes. Safe Mode appears stable, and one user reported that downgrading Excel resolved the issue.

Microsoft’s dump analysis identified a VBA stack overflow in VBE7.DLL, but the exact call chain has not been captured yet since TTD trace ends up causing excel hang issues. We also tested an endpoint-security exception without resolving the issue.

Has anyone seen similar VBA or add-in compatibility problems with Version 2608? Is there a recommended earlier build for a controlled rollback test?

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Answer 1

Lin v 1,550 Independent Advisor

Hi Raiyan,

Thank you for providing the detailed information.

Based on your description, may I ask if you have tested with the OneStream VSTO/COM add-in temporarily disabled?

Since Excel appears stable in Safe Mode, this may help determine whether the issue is related to the add-in itself or its interaction with Version 2608.

If the issue persists with the add-in disabled, and given the troubleshooting already completed, I would suggest engaging Microsoft Support if you haven't already done so. If you do not have the necessary permissions to open a support request, you may need to work with your administrator or IT team to do so.

I also noticed that one user reportedly regained stability after rolling back to an earlier build. You may consider validating the same rollback on a small group of affected users. If the older build proves stable, it could serve as a temporary workaround while the issue is being investigated further.

I hope everything gets sorted out soon.

Raiyan Ahmed 0 Reputation points

2026-10-08T17:18:31.78+00:00

Hi Lin, thank you for the response.

We are currently performing this isolation test by disabling the Excel and COM add-ins and then re-enabling them individually. The testing is still in progress, so we cannot yet confirm whether OneStream or another add-in is involved.

What we know so far,

Excel usage with no add-ins or macros enabled- works fine

Excel usage with all add-ins and VBA Macros enabled as our users work on per usual- Crashes, specifically when they click on a button which engages the add-in (xlam) file. This started on August 19th.

We already have an active Microsoft Support case. And yes, we are arranging a controlled rollback test for a small number of affected users, to see if its related to the latest build. Just checking here if anyone has faced a similar issue recently.
Lin v 1,550 Reputation points Independent Advisor

2026-10-08T17:43:00.34+00:00

Hi Raiyan,

Thank you for the update. It sounds like you already have the right troubleshooting steps in progress and an active Microsoft Support case.

I have not personally seen a similar report recently, but hopefully other community members who have encountered the same behavior can share their experience.

Wishing you all the best with the investigation, and I hope you are able to narrow down the cause soon.