In SOLIDWORKS 2015, there is a breaking change causing 3rd party data loss when saving a document with SOLIDWORKS 2015.
Smap3D applications use this 3rd party data storage streams to hold some information.
Therefore it is important and inevitable to perform the Smap3D parts conversion with the Smap3D SOLIDWORKS 2015 conversion tool to save Smap3D data storage (standard and repetition parts) before starting to work with Smap3D parts in SOLIDWORKS 2015 or its future versions.
In this PDF document the workflow is described step by step:
Conversion of Smap3D parts for SolidWorks 2015 
Video guide to converter tool for SolidWorks 2015