Troubleshooting

Quick fixes for common issues. If you don’t find your answer here, email support@donglecontrol.com.

Projector Output

Projector shows a black screen when it should have content

  • Check that you’ve pressed Space to go live (not just staged)
  • Look for the green indicator on the thumbnail — if there’s no green, nothing is live
  • Make sure the projector window is on the correct display (Settings > Displays)

Projector window is on the wrong screen

  1. Open Settings > Displays
  2. Select the correct display for the projector output
  3. The window will move to the selected display

Content looks stretched or cropped

  • DongleControl outputs at 1920x1080 by default
  • Ensure your projector is set to its native resolution
  • Check the projector’s aspect ratio setting (should be 16:9, not 4:3)

Keyboard Shortcuts

Shortcuts aren’t working

  • Make sure DongleControl is running (check the dock/taskbar)
  • On macOS, you may need to grant Accessibility permissions: System Settings > Privacy & Security > Accessibility
  • Restart DongleControl after granting permissions

Space bar triggers other apps

  • DongleControl registers global shortcuts — if another app is claiming Space, there may be a conflict
  • Close other presentation software that might register global shortcuts

Remote Control

Can’t connect from my phone

  • Ensure your phone is on the same Wi-Fi network as the computer
  • Check the IP address is correct (shown in Settings > Remote)
  • Try http:// not https:// — the remote doesn’t use SSL
  • Check your computer’s firewall isn’t blocking port 7770

Remote is laggy

  • Move closer to your Wi-Fi access point
  • Use 5GHz Wi-Fi instead of 2.4GHz for lower latency
  • Ensure the network isn’t congested (many devices streaming video can cause lag)

Video Playback

Video doesn’t play

  • Check the file format — MP4 (H.264) is the most reliable
  • Ensure the file path is valid and the file hasn’t been moved
  • Large video files may take a moment to load — wait a few seconds after staging

No audio from video

  • Check your system audio output is set correctly
  • Ensure the projector or speaker is connected and not muted
  • DongleControl plays audio through the system default output

NDI

NDI stream not visible on the network

  • Both devices must be on the same network subnet
  • Check your firewall allows mDNS traffic (port 5353/UDP)
  • Restart DongleControl — NDI discovery can take a few seconds
  • See the NDI Receiver Troubleshooting guide for more

Performance

App feels slow or laggy

  • Close other resource-heavy applications
  • Check that you’re not running on battery power (GPU throttling)
  • For video-heavy presentations, ensure your machine meets the minimum requirements:
    • macOS: Apple Silicon (M1 or later) recommended
    • Windows: Modern GPU with hardware video decoding
    • Linux: X11 with GPU acceleration enabled

High CPU usage

  • This is normal during video playback or NDI streaming
  • If idle CPU is high, check for stuck processes and restart the app