Hi @Anna Zuckerman,

I noticed you commented on another thread (below) and I left you a reply there on best next steps. 

You are on the right track with importing a .csv file, that is the first step in the solution. I recommend reading through the rest of my reply in that thread for the second half of the solution.

I also included in my reply in that thread something that will assist you with your import. Since these users already exist in Klaviyo, you only need to import the “Email Address” field in the .csv file from Shopify into Klaviyo, we will retain all other information about the profile (Placed orders, custom properties etc.) Ensure you only have a single column header “Email Address” and all other columns/cells in the .csv are deleted. Also ensure you are using the “String” data type on the mapping page. Mapping just a single field will make the import much easier (I assume you are importing multiple properties for each user at the moment).

If you want a visual of what that .csv file should look like for just email address, I have an example of what that looks like in the thread below:

Lastly, if you have a welcome flow or another flow triggered off of the list you’re importing users into, ensure you set those flow emails to draft mode before actioning the upload, otherwise adding these users to the list will trigger the flow. Wait 20 minutes or so until after the upload is complete before turning the flow emails back to live (unless you want these users to receive the flow of course).

I hope that is helpful