There are two different ‘layers’ of marking something complete in Language Fuel Training courses.

First, there is the course file itself, which has internal completion records, as you can see below.

What this  means is if you are half way through a course, but exit, Next time you open the course file, the course will go to the place where it stopped last time. So the course file itself will record where you were up to.

Second, there is the 'site' completion record, as shown below.

 This record only shows 100% when all of the internal course files have been completed. Because most of our courses have just one course file, with all of the lessons inside, the site completion record for most courses will be sitting at 0% or 100%.

So if you see the 0% completion note on a course, even though you have started it, just open up the course again, and you will see an internal completion record there which will tell you where you're up to. When you complete the course (and press the 'complete' button), it will tell the site you have finished, and the site record for that course will change to 100%.