If you are having issues where Teams is not displaying file tabs properly or other similar issues it may be time to clear out the cache that Teams relies upon. You may see error messages such as the one below when trying to access resources in Teams.
On a Windows PC:
On a Mac:
If Teams is still running, right-click the Teams icon in the dock, and then select Quit, or press Command (⌘)-Q.
In the Finder, open the /Applications/Utilities folder, and then double-click Terminal.
Enter the following command, and then press Return:
rm -r ~/Library/Application\ Support/Microsoft/Teams
Restart Teams.