Hi Kevin,
I'm using version 4.28 and i'm using the sample excel file from this website and adding products in one by one and import them using products import function from smith cart. The first time it import everything perfectly, but when i'm making changes to the spread sheet (i.e. add in the thumnail name), reimport the same spread sheet, it said "import successfully" but the data didn't get updated in my case i'm adding images name.
Thank you for your help.
Jonathon