Microsoft is working to resolve a known issue that is causing delays or preventing some users from opening the Microsoft Teams desktop client on Windows systems.
The company has confirmed (tracked as) this known issue. TM1466820) on Thursday at 4:45 p.m. EDT and advised affected customers to work around the issue by using the web or mobile platforms.
“Especially when opening Microsoft Teams on Windows devices for the first time, some users may not be able to initially load the client or may experience loading delays of up to two minutes,” Microsoft said in an incident report seen by BleepingComputer.
“While we focus on remediation, affected users may be able to avoid the impact by using Microsoft Teams on the web or alternative Teams access methods such as the Teams mobile app.”
Microsoft continues to analyze service logs and telemetry data and has also reached out to some affected users to determine the root cause and determine mitigations.
At the same time, we are investigating an issue that prevents Mac users from joining Teams calls and meetings that are marked as tracked TM1466659 and confirmed on Sunday at 8:32 a.m. EDT.
While Microsoft initially blamed a code change for the Teams calling and meeting service infrastructure being unable to process some requests, the company is re-investigating the root cause after further review found that may not be the cause of the impact.
“Users may not be able to join calls or meetings in Microsoft Teams for Mac,” it said. “We are reassessing our understanding of the root cause and reviewing service logs to isolate the cause of the impact so we can determine our next steps to resolve the impact.”
In April, Microsoft fixed another known issue that prevented some Microsoft Teams Free users from chatting and calling others.
Also confirmed on Tuesday was a bug that caused crashes and startup errors for Microsoft Teams and new Outlook users after installing Windows security updates released since Patch Tuesday in August 2026.
Today, Microsoft informed customers that an ongoing Exchange Online issue affecting multiple mailboxes and triggering “Server Busy” errors delays the sending and receiving of email to external domains.
This is a developing story…
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