Need to send a email to the clients that have not purchased for 120 days from now?

@the permalinks 

Before answering your question just one note.. You named the segment “Customers who haven’t purchased for the last 120 days” so I assume you want people who placed at least one order before (because you call these people Customers). So probably you need another definition for your segment and that is placed order at least once overall.. so the segment would look something like this:

• placed order at least once overall (these are customers)
• placed order zero times in the last 120 days
• person is not suppressed for email

Then about people who are already in the segment there are few things you can do:

1. You can back populate the flow or now that is called Add past profiles (in Manage Flow). Issue you may face here is if you have a dynamic code in the flow this would be more complicated. But if not you can just add the profiles that are already in the segment to go through the flow.
2. Clone this flow triggered by an empty list. Prepare that flow and make it live, and then download the people from the segment above and upload them to the list and with that they will trigger the flow.
3. Or what I would suggest is this third option because this sounds like Win Back flow is to create it like usual Win Back flow. Trigger Placed order flow filter Placed order zero times since starting this flow, add the time delay for the first email in this flow to 120 days and then simply back populate / add past profiles to the flow. This would be probably the most appropriate (just it wont email all the people from your segment but only those who didn’t placed orders in last 120+/- days depending on when they placed their order and how long is your flow) For the people who wont get in this flow with adding past profiles you can do the 2nd option i guess..