Course Not Marking Complete

Over the past couple years, my company has developed a number of courses using Articulate 09 Publishing Suite.  During this time, we have many users who complete one or more courses, but our LMS will not mark the course complete.   As an IT Support person for this product, the number one answer is to clear temporary internet files.   The user must retake the course from the very beginning but this works 99% of the time. 

As we are now pushing Windows 7 to our user population, this issue seems to be more prevalent.

Some of the courses are 45-60 minutes in length.   A user doesn't want to complete the training again as time is a rare commodity.

Is there a more permanent fix for this problem?  Does Articulate 13 handle this issue better?   If there isn't a better resolution, we may need to look at another publishing tool.

Thank you... Shawn