Several different problems can often be fixed in Teams by clearing Teams' cache. 

They are:

• The Teams app not launching properly and instead showing a message that says, "We're sorry--we've run into an issue."
• Inability to log in to Teams.
• Missing or different information compared to what the web version of Teams displays.
• Inability to find users or teams.
• General slowness.
• Profile pictures missing or showing outdated images.
• Status not updating.
• Background images not showing.

To clear Teams' cache, follow the instructions below.

Clear the Teams Cache on Windows

1. Right-click the Teams icon located in your system tray (located in the bottom bar) and select Quit. 
2. Hold the Windows key while pressing the R key. 
3. Run will launch. In it, enter or paste %localappdata%\packages\msteams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams
4. Click OK. 
5. Delete all files and folders in this directory. 
6. Start the Microsoft Teams app.

Clear the Teams Cache on a Mac

1. Quit Microsoft Teams, and also quit Microsoft Outlook if it is running.
2. Switch to Finder. You can do this by clicking the Mac desktop.
3. From the top menu, select Go, then from the drop-down menu, select Go to Folder. 
4. Copy and Paste the following line of text into the box that appears and hit Return.
   ~/Library/Group Containers/UBF8T346G9.com.microsoft.teams
5. Move the contents of the folder to the Trash. (One way to do this is to select all with control–A, right- or control-click one of the items, and then select Move to Trash.)
6. Repeat steps 3-5, substituting the following text in step 4.
   ~/Library/Containers/com.microsoft.teams2
7. Relaunch Microsoft Teams.