Audiobook downloads to Sansa Clip + duplicate some parts and omit others

I download audio books using Overdrive Media Console to my Sandisk Sansa Clip +.  Although all parts are downloaded only once, they show up on my player twice and some of the parts not at all.  I’d really appreciate some help.  ( I have only a rudimentary understanding of  computer terminology so if you can keep it simple that would be a great help)

I’m assuming you download to your computer and then use Overdrive’s software to transfer to your device. 

By default, the Overdrive software transfers the files to "[drive letter]:", but it’s important for the files to get transferred to the “audiobooks” folder when the files aren’t tagged correctly, which it sounds like yours aren’t. 

In the software, when you tell it what device to transfer it to, go into “Advanced Options” and give it the “[drive letter]: \audiobooks” path. 

Using this method, I’ve never had an issue with Overdrive books.