Teams not working on Mac

Dear @TPH,

Thank you for reaching out to the Microsoft Q&A Community.

I'm sorry to hear that you're having so much trouble with the Teams desktop app. That is a very frustrating situation, especially when it's making your work so difficult. The error message CoreError::CDL_WORKER_FAILURE points to a deep-seated issue with Teams' data and cache, which isn't always fixed by a simple reinstallation.

Even though you've cleared the cache, Teams stores data in several different locations on a Mac. A corrupted file in one of these hidden folders can cause the entire application to fail.

Here are some steps to fully reset and fix the Teams app on your Mac.

1.Fully Quit Teams

Before doing anything else, make sure Teams is completely closed. Right-click the Teams icon in your dock, hold down the Option key, and select Force Quit.

2. Manually Delete All Teams Files

You must delete all folders and files related to Teams on your Mac to ensure a clean slate.

• Open Finder.
• Click the Go menu at the top of the screen.
• Hold down the Option key, and then select Library from the dropdown menu. This will open the hidden Library folder.
• Navigate to the following folders and drag everything that is related to Teams to the trash.
• ~/Library/Application Support/Microsoft/Teams
• ~/Library/Application Support/com.microsoft.teams
• ~/Library/Caches/com.microsoft.teams
• ~/Library/Containers/com.microsoft.teams
• ~/Library/Group Containers/UBF8T346G9.com.microsoft.teams
• ~/Library/Preferences/com.microsoft.teams.plist

After you've deleted all these files, empty the trash.

3. Reinstall Teams

• Go to the official Microsoft website and download a fresh copy of the Teams app. Avoid using the App Store to ensure you get the latest and most complete installer.
• Run the installer and sign in.

In the meantime, you can use the Teams web app or an incognito window to access all of your chats, meetings, and files without any installation issues.

If the error persists after these steps, the issue may require more in-depth diagnostics. I recommend that the Global Admin in your organization create a service request with Microsoft Support. A technical support engineer can perform a remote session to investigate the situation, verify the backend configurations, and run any necessary synchronization tools to resolve the problem. If the issue requires further attention, they can escalate it to a specialized team for deeper analysis. Ask The Global Admin in your organization to create a service request with Microsoft support to get advanced technical assistance and diagnostics. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin.  

For additional assistance, use this link to find the appropriate contact number: Global Customer Service phone numbers - Microsoft Support 

I truly hope you get your issue resolved swiftly. Please know that even though I can't directly intervene, directing you to the correct, specialized support is the most effective help I can provide from my position. I'm sincerely sorry that I can't assist you further at this stage, but this matter may be beyond our current capacity. Once you have a Support Ticket ID, you can share it with me here in the Microsoft Community via a private message. This will allow me to track the progress and ensure your case receives the necessary attention. 
I hope this information helps clarify the situation and provides you with workable solutions. Should you have any further questions or need additional assistance, please don't hesitate to reach out. We're always here to help. Have a wonderful day!

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