Classic Outlook Error

Question

I have a new error that popped up this morning for Classic users. If a user opens email and right clicks the Classic version will close out and reopen asking if you want to use safe mode. I googled the error and it gave me 4 options to fix.

1.) Run in Safe Mode

2.) Disable Add-ons

3.) Run repair through Apps and Features

4.) Make sure all is up to date.

I have done all of these and still no joy. My company has a lot of users that want Classic working, Including our CEO. Please let me know if this can be fixed without going to New Outlook. Thanks!

Answer 1

Dear Stephen,

Good day, and I appreciate the detailed description of your issue. As a forum moderator, I genuinely wish I could directly access your account or delve into the backend systems to diagnose and fix this for you. However, our role here is limited to providing general guidance and solutions that can be applied by users. 

From your description and my research, this looks like a Classic Outlook issue starting around March 12, 2026. The issue has been investigated as Microsoft 365 issue EX1254044 and was marked as fixed.

For reference: Classic Outlook crashes and opens in Safe Mode starting March 12 2026 | Microsoft Support

However, I have seen a very recent user report describing a similar problem here: Cannot open Outlook Classic, shuts down without message - Microsoft Q&A, which suggests that either the same issue has resurfaced, or this may be a new variation tied to a recent Classic Outlook build. I have also checked the Microsoft 365 Service Health Dashboard, and at the moment there is no new active incident reported regarding this behavior.

For an issue of this nature, the most reliable path forward is to have the Global Admin in your organization open a service request with Microsoft Support. A technical support engineer can perform a remote session to investigate the situation, review your Office build and channel, gather crash logs, and run any necessary diagnostics. If the issue requires further attention, they can also escalate it to a specialized team for deeper analysis, which is especially useful if this turns out to be a new, unreported variation of the issue. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin. If you don't know who your IT administrator is, please refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support 

For additional assistance, use this link to find the appropriate contact number from your region: Global Customer Service phone numbers - Microsoft Support 

I know this isn't the answer you were hoping for, and it's disappointing when the solutions aren't straightforward. Please know that as a forum moderator, directing you to the correct, specialized support is the most effective help I can provide from my position. I truly hope you get your issue resolved swiftly. Wishing you all the best. 

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