New Teams users: MS is saying to exclude the msteams and msteams-update process from your AV vendor. In MS defender for endpoint to exclude a process (and not the files that the process opens) you have to put that process with its full path in the excluded path section. It appears that the teams folder path changes in the new teams. Its now C:\Program Files\WindowsApps\ MSTeams_23247.1112.2396.409_x64_8wekyb3d8bbwe and changes. Since we need the full path does %ProgramFiles%\WindowsApps\MSTeams_*?*_\ms-teams.exe work? Notice the question mark which is a suported wildcard in MDE.