To resolve this, I followed these steps:
- Go to C:\Users\USERNAME\AppData\Local\Autodesk\Navisworks 2016\LocalCache
- Select all
- Re-open the models in Navisworks
- You will see that the cache folder immediately starts to fill up again with the new models.
Here are some other Glue cache locations...
Glue 2015 cache location:
Glue 2016 cache location:
When directly appended to Navisworks, you can see the originating file name, such as: