Hello, I see this was posted 3 years ago and Im still experiencing the same problem, seeing the same error window as all of you above. I was expecting to simply download CSV file with all my products from Shopify and simply import it (as advised by Squarespace) to Squarespace.
I am attaching two raw files I downloaded from Shopify. One is plain CSV, the other was said to be CSV for Excel etc. I did not edit them at all.
I gotta say, I am also experiencing the same problem when importing old mailing contacts.
I was hoping to get a smooth transfer as all Squarespace articles suggest there is, but i am spending with it more time than I would like to....