Microsoft Teams is one of the most widely used business communication tools — which makes it all the more frustrating when it stops working, especially just before a meeting. Most Teams problems fall into one of a handful of categories, and most can be resolved without contacting IT. Work through these steps in order.
1. Check whether Microsoft itself has an outage
Before troubleshooting your own setup, it's worth confirming that Microsoft's services are actually running. Occasionally Teams — along with other Microsoft 365 services — experiences a widespread outage that affects many users simultaneously.
How to check:
- → Visit status.microsoft.com — this is Microsoft's official public status page. If Teams is listed with an incident, there is nothing you can do except wait for Microsoft to resolve it.
- → You can also check downdetector.com to see if other users are reporting similar problems right now.
If there's a Microsoft-wide outage, skip the remaining steps — the fix is outside your control.
2. Sign out and sign back in
Teams uses authentication tokens that can expire or become corrupted — causing errors like “We couldn't sign you in”, missing messages, or features that simply stop responding. Signing out and back in forces Teams to generate a fresh token.
Sign out of Teams
Click your profile picture in the top-right corner of Teams and select Sign out.
Close Teams completely
On Windows, right-click the Teams icon in the system tray (bottom-right corner of your taskbar) and choose Quit. On Mac, right-click the Teams icon in the Dock and select Quit.
Sign back in
Reopen Teams and sign in with your work Microsoft 365 account. Allow it a minute to fully load before testing.
3. Clear the Teams cache
Teams stores temporary data locally to improve performance. Over time this cache can become corrupted, causing strange behaviour like missing messages, channels not loading, or Teams crashing on startup. Clearing it forces Teams to rebuild its local data from scratch — it does not delete any of your messages or files.
How to clear the Teams cache
Windows
- 1. Make sure Teams is fully closed (quit from the system tray)
- 2. Press Win + R to open Run
- 3. Type %appdata%\Microsoft\Teams and press Enter
- 4. Delete the contents of the folders named Cache, blob_storage, databases, and tmp
- 5. Reopen Teams and sign in
Mac
- 1. Quit Teams fully
- 2. Open Finder, click Go > Go to Folder
- 3. Type ~/Library/Application Support/Microsoft/Teams
- 4. Delete the Cache folder
- 5. Reopen Teams
This is safe — it only removes temporary data. Your messages, channels, and files are stored on Microsoft's servers, not locally.
4. Microphone or camera not working in meetings
Audio and video issues in Teams are very common — particularly after Windows updates, which sometimes reset device permissions. There are two things to check: Teams device settings and Windows privacy settings.
Check Teams device settings
In Teams, click your profile picture > Settings > Devices. Make sure the correct microphone, speaker, and camera are selected. Use the Make a test call button to verify they are working.
Check Windows permissions
On Windows, go to Settings > Privacy & Security > Microphone and Camera. Make sure the toggle for Microsoft Teams is switched on. On Mac, go to System Settings > Privacy & Security > Microphone / Camera.
Check physical connections
If you use a headset or external webcam, unplug and re-plug the USB or audio jack. Try a different USB port. Teams sometimes doesn't detect a device that was plugged in after it started.
Restart Teams after plugging in devices
Teams reads device availability at startup. If you plugged in a headset or camera after Teams was already open, close and reopen Teams to make it recognise the new device.
5. Try the browser version of Teams
If the desktop app is misbehaving and you have a meeting imminent, the browser version of Teams is a reliable fallback. Go to teams.microsoft.com in a modern browser (Edge or Chrome work best) and sign in with your Microsoft 365 account. It has nearly full functionality and is often quicker to load.
VPN users
If you're connected to a VPN, try disconnecting it temporarily and testing Teams again. Some VPN configurations route Teams traffic in a way that causes connection or audio quality issues. If Teams works without the VPN, speak to IT about split tunnelling — a configuration that allows Teams to bypass the VPN while keeping everything else secure.
When to call IT
Contact IT if none of the above resolves the issue, or if you encounter any of the following.
- !Teams shows a licensing error or says your account doesn't have access
- !You can't access specific channels or teams that colleagues can see
- !Teams crashes repeatedly after clearing the cache
- !You're missing entire conversations or files that should be visible
- !The problem affects your whole team, not just your device
Need help before a meeting?
If you're a StormDotCom client and Teams is causing you problems, get in touch. We can diagnose the issue remotely and get you back up and running quickly.
Contact the Help Desk