How to bulk update only the "Accepts Marketing" info on a customer with CSV import?

[Omnitype]

We are moving from a third-party email marketing platform that did not sync well with Shopify. So when customers subscribed or unsubscribed from our list, it did not always correctly sync to their account in the Shopify backend. We are trying to get all the customers' accept marketing status to reflect correctly in Shopify.

We have 36,000 customers and it is not feasible to go one by and one and check that their marketing status is correctly reflected in Shopify.

So our plan was to use the csv template from the import button on the customer page to bulk update all these customers marketing status. We just downloaded the template, insert the customers first name, last name, email, and accept marketing status (yes or no), and then re import the csv to change the info on the accounts that match those emails. 

We tested on a small amount of customers first, just in case something went wrong. We didnt want to destroy 36000 customer accounts. And were glad we did. 

When we import the new csv Shopify takes a blank cell to mean "delete info" instead of just skipping it. So on our test customers, but because we only filled in their name, email, and marketing status, it erased all info on their account accept those things. 

We have found no way, even after talking to a Shopify Plus CS rep, to only change the info in cells that are filled in. The Import feature seems to be all or nothing. Anything that is left blank will be deleted. THIS IS A HUGE BUG. I actually dealt with this issue a couple years ago when I first got on the platform and actually completely erased everything on like 20,000 account because of this. I assumed it would have been fixed by now, but no.

- We are not going to go in and manually add all the account info to the csv so it doesn't get deleted.
- We are not going to download the customers from the current Shopify store (that would have all the info) and reupload because then we would have to manually find those 36000 specific people in a csv with 80000+ names on it.
- We are not going to manually type in all 36000 emails into the Shopify search bar to check and update their status. 

HOW CAN WE POSSIBLY UPDATE JUST ONE PIECE OF INFORMATION ON CUSTOMER PROFILES WITH CSV IMPORT??

CSV import is completely broken (like many Shopify features) and the CS rep told me to download an app to do it. 

We are trying to be responsible and make sure that the customers who unsubbed stay unsubbed when we move to our new marketing system, but Shopify legit is not allowing us to make this happen because their system just doesn't work. 

[mnearents]

@Omnitype Did you ever solve this, and if so, how? Same problem here. 

[alexdco]

Same here

[Omnitype]

No we never did 😩

[mnearents]

Klavio told me all I need to do is export my segment and then imported into Shopify. But I thought that if the columns weren’t the same that data would get deleted in Shopify. But I did a test import of one customer where I only imported first name, last name, email, and subscription status, and the subscription status updated, and nothing was deleted. (Tags, metafield, etc. ).

i’m gonna do some more testing, but it looks like I can just upload a spreadsheet of emails and subscription statuses and it would work.

[alexdco]

We managed to solve it using Matrixify to update our customer lists. Costly, but it has allowed us to import our newsletter list after our initial customer upload.