Microsoft Outlook has been the dominant email client for decades. Millions of individuals and businesses rely on it for communications. Many would argue that other tools, mostly associated with smartphones, have taken the place of email. That's true to an extent, but when serious matters are involved, email remains key. It Outlook is not working, many are affected.

When Microsoft suffered its major outage of cloud services, including Microsoft 365, on November 12, 2026, Outlook stopped working. From published reports from services such as DownDetector and Microsoft's own Health Status page, complaints about Outlook being "down" showed up early and often. But how can Outlook be down? Isn't it just an app, a general-purpose email client?

No. Outlook started that way 30 years ago as an app in Microsoft Office 97. But today, Outlook is part of Microsoft's 365 cloud service. When it launches, it phones home. If it cannot find what it's looking for, it may not even show its splash screen, much less the full UI. This gives the appearance that it did not launch at all, but a quick look at Task Manager (or TMOG) will show outlook.exe running as a backup task. It's stuck; attempts to launch it again will be fruitless. It can be terminated with Task Manager so that it can be launched from scratch again, but it may still get stuck.

If it does manage to sort itself out enough to present the UI, it may still not be possible to access email accounts. If Microsoft's cloud services are down, as they were in this case, email accounts provided by Microsoft will be unreachable. This results in a tiny notification at the bottom of the Outlook window stating that the account is disconnected. But when this process happens, Outlook may go into its general "working offline" mode.

I have Outlook configured to handle four email accounts, three of which are provided by Microsoft. The fourth is a backup account - Gmail. With disconnected Microsoft accounts and Outlook having gone offline, Outlook did not attempt to retrieve email from the Google account. In other words, Outlook was "down."

This should not happen. If one account is inaccessible, an email client should not block access to other accounts that are accessible.

Microsoft would very much like to eliminate desktop apps - those that run locally on your PC - in favor of browser-based apps. That's what Outlook (new) is all about. But then a Microsoft cloud outage could be even worse. Outlook would not run at all, and neither would Word, Excel, PowerPoint, OneNote, OneDrive, Teams, or anything else. Microsoft Copilot is already strictly a Web app, and it has been offline for the last day.

This outage has severely impacted my own work. Fortunately, the two OneDrive accounts on which I rely seem to remain available. But because in both cases I sync the cloud and my PC, and because apps such as Word run on my PC without depending on cloud assets, I can continue to write. In spite of that, I think I'm operating at 50%. I know of at least one law firm, with personnel dispersed around the US, that is nearly incapable of doing business as a result of this outage. The absence of Outlook is central, and this outage is devastating.

Microsoft's statements about what went wrong are very vague. It has promised a full explanation once the event is over. I'm sure that will be filtered through legal and PR, and thus doubt transparency will prevail. Microsoft has also said the outage was not the result of a malicious attack. I doubt Microsoft will be entirely forthcoming about that, either, because it would cast doubt on the company's ability to operate a secure cloud environment.

Because Outlook is no longer a standalone email client and instead has deep tendrils into Microsoft's cloud infrastructure, it can no longer be trusted with our email. It's one thing to have Microsoft's email services go down and quite another for the email client to not work at all, even for other, non-Microsoft email accounts.

Consider Thunderbird instead.