At the stage of Input->Inventories you could ONLY load one of the available inventories on data matrix. 

In order to use Inventories for category building it is need in the Endpoint stage to select one or more inventories and after that to define a category by using of any of the profilers in the Category definition section.

Keep in mind that:

1. LMC does NOT recommend performing a category using Inventories since the Inventories do not include experimental data. The difference between Inventories and Databases is that Inventories include ONLY chemical information without data.

2. In addition to the latter, the Inventories in Toolbox are not cached, which means they are not profiled and also 2D/3D parameters are not calculated. In this respect, if you use Inventories for building a category this will be time consuming operation. Based on this we recommend to use Databases instead of Inventories for building your category.