Knowledgebase Home: 20. Recent Issues
I'm having trouble hearing or viewing lectures
Posted by on 16 February 2012 09:50 AM

Before you submit a support ticket, make sure you have passed all points on the How do I check the compatibility of my computer with Canvas page, and read the following information:

  1. Unable to see lecture:
    • 404 or other error. This is a broken link. Please file a support ticket stating the lecture number and class (ex. DEMO1234 - Demo Class) in which you encountered the error, and a technician will fix it as soon as possible.
    • Missing plug-in. Be sure you have installed the latest version of Adobe Flash, available at Once you've completed the installation, quit and re-open your browser.
    • iPad or other iOS-based device. The majority of lectures in CGCE online courses are based on Flash, which is not supported by iOS. Please use a computer to access them.
  2. Unable to hear lecture:
    • Check your speakers or headset volume. If the volume appears set correctly, make sure your computer is using the correct sound output:
      • OS X users: Option-click the speaker icon next to the clock in your menu bar. Choose the desired Output Device.
      • Windows 7 and Vista users: follow the tutorial located at
      • Windows XP users: Go to the Control Panel (Start > Control Panel) and open Sounds and Audio Devices. Alternatively, right-click on the speaker icon in your system tray next to the clock, and select "Adjust Audio Properties." Make sure the correct devices are selected under the "Audio" tab.
  3. "No Audio" displayed on status bar of Adobe Presenter lecture:
    • Adobe presenter has a known playback incompatibility with Adobe Flash on OS X Lion (10.7). Try plugging in a pair of headphones, either USB or standard stereo jack, and emptying your browser cache:
      • Safari: "Safari > Empty Cache ..." or Option-Cmd-E. Reload the lecture page.
      • Firefox: "Tools > Clear Recent History." Set "Time Range to Clear" to "Everything" and uncheck all boxes except Cache. Once cleared, reload the page.
      • Chrome: "Chrome > Clear Browsing Data ..." or Shift-Cmd-Delete. Reload the page.
    • If clearing your browser cache and reloading the page does not force audio to play over the attached headphones, unplug them and reload the page.
    • To learn more about this issue, click here.

If you're still having trouble hearing or viewing lectures after following the instructions above, submit an online support ticket.

See also:

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