Start sharing from the app or browser you actually use. Then open Apple menu → System Settings → Privacy & Security → Screen & System Audio Recording. Turn on the app there. If it is missing and the list has an add button, use it to select the app.
01Give permission to the app that captures the screen
Section linkIf you join a Teams meeting in Chrome, check the permission for Chrome. If you join in the Teams desktop app, check Microsoft Teams. Start a screen share to give the app a chance to show the macOS request. If the prompt offers Open System Settings, use it to jump to the right list.
02Choose the list that includes the screen
Section linkIn Screen & System Audio Recording, choose the list for screen and audio rather than the option for audio only. Turn on the app’s switch, or add the app with the button below the list if available. Grant access only to software you trust. If macOS or the app asks you to quit and reopen, rejoin the meeting after it restarts.
03Test with a window you can safely share
Section linkShare an ordinary window, such as a blank document. If the app can see the window but the meeting still will not let you present, ask whether the host allows participants to share. If the Mac will not let you change the permission, check with its administrator. A microphone or camera switch will not grant screen access.