Microsoft told users on Monday evening that it was working on a fix for Outlook, Exchange Online, and other Microsoft 365 business services that were down for much of Aug. 31.
"We're continuing to deploy our mitigation across the affected environment and users should begin to see gradual recovery to mail flow," the official Microsoft 365 status account wrote on X at 7:47 P.M. ET / 4:47 p.m. PT. "In parallel, we're restarting targeted sections of the affected infrastructure to aid the recovery of the downstream scenarios."
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"The gradual recovery to mail flow" didn't satisfy some Microsoft customers, who responded to the X update by asking for more specifics on timing.
"What is the estimated time for full recovery? Admin Center shows vague information too," wrote one user. Another X user noted that some of their email was starting to roll in "slowly."
At 11:52 p.m. ET / 8:52 p.m. PT, approximately four hours after Microsoft's update, the company posted that mailbox connectivity should have returned to normal. However, it noted that it was still working on restoring search functionality, and that it may take a while for backlogged mail queues to clear "due to the volume of previously queued messages."
The problems initially began at the start of the workday on Monday, when many Microsoft users complained on sites like Downdetector that they could not access their Outlook email. Other app-related problems and login issues were also noted, along with issues with Microsoft Exchange Online, "a cloud based messaging platform that delivers email, calendar, contacts, and tasks."
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UPDATE: Sep. 1, 2026, 2:39 p.m. AEST This article has been edited to add updates from Microsoft.