As of October 28, 2018 Shopify will no longer allow you to import orders that have a line item quantity less than 1. They are making the change to ensure consistency throughout their platform as they do not allow orders with a line item quantity of less than 0 to be fulfilled.

In order to comply with the changes we have recently released a new validation rule that throws an error if your order has a line item quantity less than 1.

There is no way around this so if you are trying to run an import and the quantity is less than 1 you will need to update your import file.

For more information about this validation change read the official announcement from Shopify.