Attribute names are case sensitive and as such duplicates can appear in the list of attributes.
Duplicates can be created when adding new product combinations during a CSV import.
For instance, the combination attribute 'Yellow' exists and you are creating a new product combination using the attribute 'yellow'. The import process will automatically create this new attribute 'yellow' because names are case sensitive, thus creating a duplicate.
With Store Commander you can remove duplicate entries with the merge option, represented by the toolbar icon in the Groups and Attributes window.
To merge duplicates, select the attributes (on an orange background) and click on the merge icon.
The attribute with the lower ID number (oldest) will be used as the main attribute and the other(s) will be deleted.
Product combinations using the deleted attribute(s) will automatically be updated with the changes made.
In the above example, ID 68 will be deleted and the 2 products using this attributes will automatically in real time be using the attribute ID 67.