Full Diagnostic Tree & Step-by-Step Overview
Which operating system and version of Microsoft Teams are experiencing startup crashes?
- Windows 10/11 running New Microsoft Teams (v2) or Classic Teams
- macOS running Microsoft Teams
- Teams freezes specifically on 'Loading Microsoft Teams...' or in an infinite sign-in loop
- Teams crashes immediately with a Microsoft Edge WebView2 runtime error
Are you running the 'New Microsoft Teams' app (indicated by a 'NEW' badge on the icon) or 'Classic Teams'?
- New Microsoft Teams (v2 / Work or School)
- Classic Microsoft Teams
Resetting New Microsoft Teams (v2) App State and Cache
Solution:
Root Cause: Corrupted AppX Package State or Stale LocalCache Database
New Microsoft Teams operates as a packaged Windows AppX/UWP application. Local database corruption in the AppX package folder will prevent the client process from rendering UI frames.
# Step-by-Step Fix:
Force Quit Teams Processes:Press Ctrl + Shift + Esc to open Task Manager.Find ms-teams.exe or Microsoft Teams, right-click and select End task.Reset via Windows App Settings:Press Windows Key + I to open Settings > Apps > Installed apps.Search for Microsoft Teams (work or school).Click the three dots (...) next to it and select Advanced options.Scroll down and click Reset (or Repair first).Manual AppData Cache Purge (If Reset Fails):Press Win + R, paste the following path, and press Enter: %localappdata%\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams
Delete all files and subfolders inside this MSTeams folder.Relaunch New Teams.
Clearing Classic Teams AppData Cache
Solution:
Root Cause: Corrupted Electron Cache Files in AppData
Classic Microsoft Teams relies on an Electron framework architecture that stores web app data across multiple local folders. Stale session tokens or corrupt IndexedDB databases trigger startup crashes.
# Step-by-Step Fix:
Quit Teams Completely:Right-click the Teams icon in the system tray (near clock) and select Quit.Verify in Task Manager (Ctrl + Shift + Esc) that no Teams.exe processes remain.Navigate to Cache Directory:Press Win + R to open the Run dialog box.Paste %appdata%\Microsoft\Teams and hit Enter.Delete Cache Subfolders:Delete all contents within the following subfolders:blob_storageCachedatabasesGPUCacheIndexedDBLocal StoragetmpRelaunch Classic Teams and sign back in.
Purging Teams Cache & Keychain Credentials on macOS
Solution:
Root Cause: macOS Container Cache or Keychain Access Token Lock
Corrupted preference property lists (.plist) or cached authentication tokens in the macOS Keychain cause launch crashes.
# Step-by-Step Fix:
Quit Teams: Press Cmd + Q or force quit from Activity Monitor.Clear App Containers (Finder):Open Finder, press Cmd + Shift + G to open *Go to Folder*.For New Teams: Paste ~/Library/Group Containers/UBF8T346G9.com.microsoft.teams and move all contents to Trash.For Classic Teams: Paste ~/Library/Application Support/Microsoft/Teams and move all subfolders to Trash.Clear Keychain Credentials:Open Keychain Access via Spotlight (Cmd + Space -> type Keychain Access).In the top-right search box, type Microsoft Teams or Teams.Right-click and delete all found credential items (e.g., Microsoft Teams Identities Cache).Restart your Mac and launch Teams.
Fixing Web Account Manager (WAM) Token Desynchronization
Solution:
Root Cause: Web Account Manager (WAM) Token Desynchronization
When your organizational Azure AD / Entra ID tenant token conflicts with stored local profile tokens, Teams hangs on boot during silent authentication.
# Step-by-Step Fix:
Disconnect Work or School Account:Go to Windows Settings > Accounts > Access work or school.Locate your corporate/school email, click it, and select Disconnect.Remove Stale WAM Accounts:Press Win + R, type control color or search for Credential Manager.Select Windows Credentials.Delete all generic credentials starting with adal, msteams, or MicrosoftAccount:user=.Re-link Account:Return to Settings > Accounts > Access work or school, click Connect, and re-enter your corporate email and password.Relaunch Teams.
Repairing Microsoft Edge WebView2 Runtime
Solution:
Root Cause: Corrupted Microsoft Edge WebView2 Runtime
New Teams relies on the system-wide Microsoft Edge WebView2 control engine to render interface elements. If the runtime binaries are missing or corrupted, Teams will instantly crash on startup.
# Step-by-Step Fix:
Repair WebView2 Control:Press Win + I to open Settings > Apps > Installed apps.Search for Microsoft Edge WebView2 Runtime.Click the three dots (...), select Modify, and choose Repair.Reinstall WebView2 Runtime (If Repair Fails):Download the standalone Evergreen Bootstrapper directly from Microsoft's official WebView2 page (developer.microsoft.com/en-us/microsoft-edge/webview2/).Run the installer as Administrator to overwrite corrupted system libraries.Relaunch Teams.