Outlook Down Today? Exchange Online Search Degradation Is the Main Issue

A trending piece from The Sunday Guardian asked whether US users were losing access to Outlook logins, the website and incoming mail. The article never shows that a large outage is happening. It mostly explains how outage trackers work and lists symptoms people could see. The evidence available at midday UTC points to a set of specific, documented faults, not a red-alert outage.

What the outage trackers show​

Two independent monitoring services did not show a major Outlook or Microsoft 365 failure on Thursday morning:

• DownForEveryoneOrJustMe said it was not detecting any problems with Outlook. It listed its last detected outage as September 2, 2026, lasting about 34 minutes. Its feed did include a handful of individual login complaints from US users early on October 1, with others from the UK, Portugal, Italy and Poland. Login problems made up 74% of all reports the site has logged for Outlook.
• IsDown, which checks Microsoft's official status data and also collects user reports, said the Microsoft 365 suite was working normally at its 12:11 PM UTC check. It had received zero user reports in the previous 24 hours.

A few scattered login reports are not an outage. Any service with hundreds of millions of users will always have someone, somewhere, who can't sign in because of an expired password, a broken MFA prompt or bad hotel Wi-Fi. Trackers flag a real problem only when reports climb well above the normal baseline. That wasn't happening.

Bottom line: the trackers show background noise, not a spike.

What Microsoft's own incident records show​

The trackers look quiet, but Microsoft's service health data doesn't. Microsoft's incident records, as republished on public status pages run by Earlham College and the University of Pennsylvania, showed Exchange Online in a "service degradation" state on October 1 with several open issues:

None of these says users can't sign in, send mail or receive mail. If your inbox loads but search returns nothing, you're probably caught up in a real Microsoft problem. If you can't sign in at all, start by looking at your own account, device and network.

The search problem: the one most people will notice​

EX1473834 is the most user-visible issue on the list, and it has been open for a while. The Penn page tracks how Microsoft's updates changed over time:

• Microsoft first tried a fix that "didn't provide the expected recovery." It then found that moving affected mailboxes to alternate database infrastructure restored search.
• Later, more users reported being affected even after that mitigation.
• Microsoft's current explanation is that the infrastructure behind Outlook search is getting more request traffic than it can handle efficiently. Engineers are still working out where that traffic is coming from.
• Microsoft's latest update says configuration changes are still rolling out and should fix the problem for everyone by its next scheduled update.

Search problems keep coming back in Exchange Online. Last month, NHS.net Connect reported on a separate incident, EX1469261, in which a portion of Exchange Online infrastructure responsible for search functionality experienced lower than expected availability, preventing some users from searching during peak hours. That incident was limited to some users in the United Kingdom who were attempting to complete searches using Outlook on the web or either the classic or new Outlook desktop apps and has been resolved. Earlier, BleepingComputer covered EX1063763, where search issues were blamed on infrastructure components responsible for processing users' search requests that perform below acceptable performance thresholds.

Search draws a lot of complaints because it's a heavy workload that people take for granted. Nobody notices it until a "Where's that invoice from March?" query comes back empty.

Quarantine, add-ins and delegates: mostly for admins​

• Quarantine (EX1478331): Microsoft says a recent service-side update introduced a code error. Admins may see 550 5.1.10 Failed to deliver to Quarantine store in message trace. Microsoft is working on a code fix and is also looking at moving affected service traffic as a second option. This one matters for security teams: if mail that policy should hold isn't reaching quarantine, check message trace for that error.
• Unwanted add-ins (EX1441488): Microsoft traced this to part of the Exchange Online add-in sync pipeline returning incorrect EnabledStatus values. As a result, Outlook automatically shows add-ins that admins had only set as "Available." Microsoft's suggested workaround is for admins to run Set-App with the -OrganizationApp, -PrivateCatalog and -DefaultStateForUser Disabled parameters (plus the add-in's identity) to remove add-ins that appeared by mistake. Microsoft expects the fix to finish rolling out by Friday, October 2.
• Calendar delegates (EX1478163): The record covers updating delegates in classic Outlook desktop only. It doesn't say calendars are broken in general.

Other Microsoft 365 workloads also have open items. A Purview bug affects Communications Compliance policies with more than four classifiers, and Microsoft expects a fix by October 5. Copilot Chat may also miss some Exchange Online messages dated from July 22 onward until they're re-indexed.

Bottom line: Outlook is up, but parts of it are broken. Search is the problem most end users are likely to run into.

About that August outage​

The Sunday Guardian pointed to a "previous major Outlook disruption" on August 31, 2026, as an example of how bad things can get. That event did happen. IsDown logged a roughly three-day Microsoft 365 incident titled "Users may experience issues when utilizing multiple Microsoft 365 services," starting August 31 at about 15:08 UTC. DownForEveryoneOrJustMe recorded several Outlook outage windows that day and into September 1, the longest lasting about five hours.

The Guardian's figure of roughly 6,015 Downdetector reports at the peak could not be independently verified from the records available, so treat it as unconfirmed. That incident is also closed. It isn't the cause of anything people are seeing today.

Outlook acting up? Check in this order​

1. Find out which account you're using. For a work or school account, the authoritative source is Service health in the Microsoft 365 admin center (Health > Service health). Microsoft's documentation says the Service Support admin and Helpdesk admin roles can view it. For a personal Outlook.com account, use Microsoft's public consumer service status page.
2. Read the incident type correctly. Microsoft's documentation calls an advisory a problem affecting some users while the service stays available. An incident means the service, or a major function of it, is unavailable, for example being unable to send or receive email or sign in.
3. Pin down the symptom. Search failing but everything else working points to EX1473834. Sign-in failing for only one user points to that user's account, credentials or device.
4. Try another client. If classic Outlook fails but Outlook on the web works (or the other way round), the fault is probably local to that client.
5. Admins: report anything that isn't listed. The Service health page has a Report an issue form. Microsoft says it compares those reports with data from other organizations and, if the problem turns out to be on its side, posts a new incident or advisory.
6. Use trackers as an early warning, not as proof. Downdetector-style sites can show that something is going on before Microsoft posts about it, but they can't tell you the scope or the cause.

The takeaway​

On October 1, "Outlook down" headlines overstate what's actually happening. Outlook is running, with several smaller Exchange Online faults that are real but limited in scope. Search is the one most people will notice, and Microsoft's records show it has been harder to fix than expected. For IT admins, the quarantine bug and the add-in sync issue deserve a look today. For everyone else, if search comes up empty, it's very likely Microsoft's problem and not something you did.