Sometimes you need to disable any compression options. For Captivate 3, click Edit > Preferences > Project > Settings.
Try clearing the compression options and see if it helps.
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I would also suggest you to try importing the complete project in a new blank Captivate project. Then try to preview / publish the same. Hopefully it will work.
Steps to import one project to another -
1. Launch Captivate project which is not getting published, say File1.cp
2. On the same setup, launch another instance of Captivate and open an new blank project, say untitled1.cp
3. In untitled1.cp, follow menu item File > Import > Slides / Objects and point to File1.cp
All the slides should get imported to untitled1.cp. Now try to preview / publish and see if it works.
Two excellent suggestions, unfortunately neither has been successful. Should I simply rebuild it?
Removing the quiz slides allowed it to play/publish. I've substituted click boxes with reporting for the quiz slides.
Thank you for your help and your prompt replies! You kept me on deadline!
Mukul's suggestion worked for me in the same situation. Thanks!