How to Fix “Something Went Wrong [1001]” in Microsoft Teams?

Microsoft Teams Error 1001 typically occurs when attempting to sign into the platform. While there can be several causes, the most common is interference from third-party antivirus software. Other contributing factors include outdated or corrupted cache files, invalid authentication cookies, and permission-related issues—especially with organizational accounts.

Now that we’ve identified the possible causes, let’s walk through the solutions to fix this error.

1. Sign Out and Sign In

Signing out and then signing back in allows Microsoft Teams to refresh session cookies, which may have become outdated or corrupted, potentially causing this issue.

1. Launch the Microsoft Teams application on your computer.
2. Click or tap your profile picture or initials in the top-right corner, then select Sign out from the dropdown menu.
3. Close Teams completely (including any background processes) and restart the application.
4. At the login screen, enter your email address and password to sign back into your account.
5. After signing in, test to see if your original issue has been resolved.

2. Disable the Antivirus Software

Third-party antivirus software can sometimes block the background services or network access that Microsoft Teams relies on. This can prevent the app from launching, signing in, or syncing properly. To rule out interference from your security software, temporarily disable your antivirus and check if Teams functions as expected.

Note: If Teams works after disabling the antivirus, add it to your antivirus’s exceptions list, then re-enable protection immediately.

1. Locate your antivirus software icon in the system tray (the group of small icons in the bottom-right corner of your Windows taskbar, next to the clock).
2. Right-click the antivirus icon to open its context menu. If you don’t see it, you may need to click the upward arrow (^) to show hidden icons.
3. In the menu that appears, look for and select one of these options:
   • Pause protection
   • Disable temporarily (typically 10-30 minutes or until next restart)
   • Turn off protection

   

4. After disabling protection, immediately launch Microsoft Teams to test if your issue is resolved. Remember to re-enable your antivirus protection afterward.

3. Clear Microsoft Teams Cache

Cache is a temporary storage system used by applications to save frequently accessed data. This helps improve performance by allowing the app to quickly retrieve information without needing to constantly fetch it from the server. However, if these cache files become corrupted or outdated, they can lead to unexpected issues within the app. Clearing the Microsoft Teams cache can help resolve such problems by forcing the app to regenerate fresh data.

1. Press Windows + R simultaneously to open the Run dialog box (a small window will appear in the bottom-left corner of your screen).
2. Type or paste this exact path into the Run box and click OK:

   %appdata%\Microsoft\Teams

   This will open Microsoft Teams’ application data folder

3. In the File Explorer window that appears, select all files and folders (Ctrl + A).
4. Press Delete or right-click and select Delete.
5. After deletion, restart your computer (recommended).
6. Launch Microsoft Teams – it will recreate necessary files automatically.

4. Run Teams as Administrator

Running the program as an administrator gives Microsoft Teams the necessary permissions to access or modify system-level files and settings that may be restricted under normal user access. If you haven’t already tried this, running Teams as an administrator might help resolve the issue.

1. Click the Windows Start button and type “Microsoft Teams” in the search bar.
2. Right-click on Microsoft Teams in the search results and select Run as administrator (click “Yes” if prompted by User Account Control).

5. Reinstall Microsoft Teams

Microsoft Teams can sometimes run into issues due to incomplete updates, corrupted files, or misconfigured settings from previous installations. Reinstalling the app removes all problematic data and installs a clean, updated version. This process also restores the app to its default settings, clears leftover conflicts, and ensures full compatibility with system components. Reinstalling is especially helpful if none of the earlier methods resolved the issue.

1. Press Windows + I to open Windows Settings.
2. Select Apps from the left sidebar, then choose Installed apps.
3. Type “Microsoft Teams” in the search box at the top of the Installed apps list.
4. Click the three-dot menu next to Microsoft Teams and select Uninstall (confirm if prompted).
5. Go to the official Microsoft Teams download page and click Download for desktop.
6. Run the downloaded installer and sign in with your Microsoft account credentials when prompted.
7. Test Teams to verify if the issue has been resolved.