Microsoft Outlook remained down for a second day, disrupting email access for users across multiple regions. The company has not yet confirmed a full restoration timeline.
The outage also affected Copilot, Microsoft’s AI assistant tool that the company has promoted heavily. The disruption comes as Microsoft works to expand Copilot adoption among business customers.
One analyst estimated the outage could cost Microsoft between $100 million and $400 million. The estimate assumes the company offers credits and other compensation to affected customers.
Microsoft’s stock slipped as the service problems persisted. Investors are weighing the financial fallout against the company’s broader cloud and productivity business.
The company has not disclosed how many users were affected or the root cause of the failure. Service updates have been posted on Microsoft’s status page as teams work to resolve the issue.
Businesses that rely on Outlook for daily communication faced delays and missed messages. Some turned to alternative channels while waiting for service to return.
Microsoft has not announced specific compensation plans. The final cost will depend on how long the outage lasts and how many customers seek credits.
