Fixes / Teams · Checked

Teams "We're sorry, we've run into an issue": how to fix it

Short answer

This Teams message means the desktop app couldn't finish starting or signing you in. Usually the local cache is corrupted, a network or proxy problem blocked the sign-in, or your saved work account token is stale. The quickest fix is to quit Teams fully and clear its cache. On Windows 11 or 10 you can instead reset New Teams from Settings > Apps > Installed apps.

What this message means

The Teams desktop app shows this message when it starts but can't load your account. That can happen at the sign-in screen or right after it. The message is generic. Teams uses it for several different sign-in and start-up failures, and there is sometimes a status code under it (for example 0xCAA70004 or 0xCAA82EE2) that points to the real cause. Your Teams account, chats and files are stored in Microsoft 365, not on your computer, so the problem is almost always on your device: the app's cached data, the Windows or macOS account token it signs in with, or the network path to Microsoft's servers. Clearing local data doesn't delete your messages.

Common causes

CauseHow to tell
Corrupted Teams cache or app dataThe error shows up every time you open the desktop app, but you can sign in fine at teams.microsoft.com in a browser. It often starts after an update or after the computer shut down while Teams was open.
Stale or broken work or school account token in WindowsOther Microsoft 365 apps (Outlook, OneDrive, Word) also keep asking you to sign in or fail to sign in. Reinstalling Teams doesn't help and the error comes straight back.
Network, proxy or firewall blocking sign-inThere is a status code under the message such as 0xCAA70004, 0xCAA70007, 0xCAA82EE2 or 0xCAA82EE7. It often happens only on the office network or VPN, or while a proxy or traffic-inspection tool like Fiddler is running.
Wrong date, time or time zone on the computerThe status code is 0xCAA20003, or your clock is noticeably off. Secure (https) connections to Microsoft fail when the clock is wrong.
Account or organization policy problemThe code is 0xCAA20004 (Conditional Access) or 0xCAA90018 (wrong credentials). Or the same error appears in the browser version at teams.microsoft.com as well, which means the problem is not just your device.
Outdated Teams app or interference from device management softwareTeams hasn't updated in a while, or your organization recently changed how it manages Macs or PCs (for example an Intune or other management agent). Clearing the cache and reinstalling both fail to fix it.

How to fix it

1. Quit Teams completely and check the basics

  1. Right-click the Teams icon in the taskbar notification area (Windows) or the Dock (Mac) and select Quit. On a Mac you can also press Command-Q.
  2. On Windows, open Task Manager (Ctrl+Shift+Esc) and end any remaining Microsoft Teams (ms-teams.exe) processes.
  3. Check that the date, time and time zone are correct and set automatically. On Windows go to Settings > Time & language > Date & time. On a Mac go to System Settings > General > Date & Time.
  4. Turn off any VPN or proxy tool for a moment, then open Teams again.
  5. If there is a status code under the message, write it down. It tells you or your IT team which cause below applies.

2. Reset New Teams from Windows Settings

New Teams on Windows 11 and Windows 10

  1. Quit Teams.
  2. Open Settings and go to Apps > Installed apps (on Windows 10: Apps > Apps & features).
  3. Search for Microsoft Teams, select the More options button (...) next to it, then select Advanced options.
  4. Under Reset, select Reset and confirm. This deletes local app data and your personal Teams settings, but not your chats or files.
  5. Open Teams and sign in again. The first start can take longer than usual while the cache is rebuilt.

3. Clear the Teams cache manually

Windows and macOS; paths differ for New Teams and classic Teams

  1. Quit Teams completely.
  2. Windows, New Teams: press Windows key + R, enter %userprofile%\appdata\local\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams, select OK, then delete everything in that folder.
  3. Windows, classic Teams: press Windows key + R, enter %appdata%\Microsoft\Teams, select OK, then delete everything in that folder.
  4. Mac, New Teams: open Terminal (Applications > Utilities) and run: rm -rf ~/Library/Group\ Containers/UBF8T346G9.com.microsoft.teams and then rm -rf ~/Library/Containers/com.microsoft.teams2
  5. Mac, classic Teams: in Terminal run: rm -r ~/Library/Application\ Support/Microsoft/Teams
  6. Restart Teams and sign in.

4. Disconnect and reconnect your work or school account

Windows 11 and Windows 10

  1. Open Settings > Accounts > Access work or school.
  2. Select the account you use for Teams and check what it says. If it reads "Connected to ... Azure AD" or "Microsoft Entra ID" on a company-owned PC, stop here and ask your IT team, because disconnecting that type of account removes the PC from your organization.
  3. If it is a regular work or school account you added yourself, select Disconnect and confirm.
  4. Restart the computer, go back to Access work or school, select Connect and sign in with your work email.
  5. Open Teams and sign in.

5. Update or reinstall Teams

  1. If Teams opens far enough, select Settings and more (...) next to your profile picture and choose Check for updates.
  2. If it doesn't open, uninstall Microsoft Teams (Windows: Settings > Apps > Installed apps; Mac: drag Microsoft Teams from Applications to the Trash).
  3. Clear the leftover cache folders listed in the cache fix above.
  4. Download the current Teams installer from microsoft.com/microsoft-teams/download-app and install it. On Windows, right-click the installer and choose Run as administrator if you can.
  5. Restart the computer and sign in.

6. Fix network or account policy errors (IT admins)

Microsoft 365 work or school accounts

  1. Test the same account at teams.microsoft.com. If the browser also fails, the problem is the account or the tenant, not the device.
  2. For 0xCAA70004 or 0xCAA70007, check for a misconfigured proxy or a traffic-inspection tool (such as Fiddler) and stop or reconfigure it.
  3. For 0xCAA82EE2 or 0xCAA82EE7, confirm the firewall allows the Microsoft 365 URLs and IP ranges Teams needs.
  4. For 0xCAA20004, review the Conditional Access policies that apply to the user.
  5. Run the Teams Sign in test at testconnectivity.microsoft.com, or the Teams Sign-in diagnostic in the Microsoft 365 admin center, using the affected user's email address.

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Still not fixed?

Use Teams in a browser at teams.microsoft.com (Edge or Chrome) while you keep troubleshooting. Browser Teams handles chats, meetings and files and doesn't use the desktop cache. If the browser version also fails, or you see a 0xCAA status code the steps above didn't fix, contact your organization's IT help desk and give them the exact code and the time it happened. They can run the Teams Sign-in diagnostic and collect debug logs. On a Mac managed by your company, mention the error to IT too, since device management agents have been known to break Teams sign-in. Home and small-business users without an IT team can open a request through Microsoft 365 support.

Questions people ask

Will clearing the Teams cache delete my chats or files?

No. Chats, channels and files are stored in Microsoft 365 and download again when you sign in. Clearing the cache or resetting the app only removes local data such as personal app settings.

What does error code 0xCAA70004 mean in Teams?

Teams couldn't reach Microsoft's sign-in server, usually because of a misconfigured proxy or a network monitoring tool. Turn off VPNs and proxy tools and try again. If it keeps happening on a work network, your IT admin needs to check the proxy settings.

Why does the error come back after reinstalling Teams?

Uninstalling doesn't always remove the cache folders or the account token Windows keeps for your work account. Delete the cache folders, and on Windows reconnect your account under Settings > Accounts > Access work or school, before you reinstall.

Teams works in the browser but not in the desktop app. Why?

That points to a problem on your device, such as a corrupted cache, a stale account token or an outdated app, and not to your account. Resetting or clearing the cache of the desktop app is usually enough.

How do I fix this error on a Mac?

Quit Teams with Command-Q and delete the New Teams cache folders in Terminal (the com.microsoft.teams2 container and the UBF8T346G9.com.microsoft.teams group container). Then reopen Teams. If that fails, reinstall Teams and ask IT whether device management software on the Mac is interfering.

Sources

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