Common Display Issues with MacBooks
When connecting a MacBook to the Teaching Station via HDMI or USB-C, you may not see your screen on the projector if the display settings are not configured correctly.
If the projector shows “No Signal” or the Mac screen flashes but nothing appears on the classroom display, try the steps below.
Recommended Display Settings:
- After plugging in the cable, open System Settings > Displays
- Select "Mirror Displays" if you want the same image on your Mac and the projector
- If using extended display mode, make sure the correct window is on the projector screen
- If the display does not appear at all, click “Detect Displays” at the bottom of the Displays window
- Try unplugging and replugging the cable, or switching to a different port (HDMI or USB-C) on the Teaching Station
- Restart your Mac if it still does not recognize the external display
Common Display-Related Fixes:
- Disable Night Shift or True Tone for more accurate projected colors
- Close the lid if using clamshell mode with an external keyboard and mouse
- Use the Mac menu bar to drag it onto the external display if it is in extended mode
Common Audio Issues with MacBooks
Even when video is working, audio may still come through your laptop speakers instead of the classroom sound system.
Steps to Fix Audio Output:
- Open System Settings > Sound
- Under Output, select the AV system (e.g., “HDMI,” “Crestron,” or the room name if labeled)
- If using USB-C, it may appear as a DisplayPort or USB Audio device
- If the correct output does not appear, unplug and replug the cable or restart your Mac
- Make sure the Teaching Station volume is up and not muted on the touch panel
- Also check your Mac’s volume using the top bar or keyboard
Important Notes:
- Macs may auto-switch back to internal speakers when waking from sleep
- Output devices may appear with different names depending on the room hardware
- Zoom may have their own separate audio settings — always check output there too
Still Not Working?
If you're still not seeing or hearing anything after checking the steps above:
- Try restarting your Mac and reconnecting
- Use a different adapter if you're using a personal dongle
- Test your laptop in another classroom if possible
Helpdesk and hours
- Fastest: Submit a support request at av.as.cornell.edu (QR code is on the projector splash and Teaching Station sticker).
- Phone: 607-882-1646
- Email: as-avhelp@cornell.edu
- Support hours: weekdays 8:00 a.m. – 4:30 p.m.
- After hours: submit a ticket or leave a message; we will review during next business hours.
- During teaching hours, call or submit a ticket immediately. We can often begin remote troubleshooting right away and dispatch a tech within about 10 minutes.