Sendable data extensions are populated by queries and automations rather than by uploads, so the file you would export is a snapshot of something that regenerates on a schedule. Deleting rows is temporary by construction.
Getting the addresses out of Salesforce Marketing Cloud
A Data Extract activity in Automation Studio, or a query into a data extension and then an export. This is an automation rather than a download button.
Before the automation that populates the data extension runs, or as a join against it. Cleaning the output of a nightly query is work that gets undone by morning.
What Salesforce Marketing Cloud does with the file you bring back
The import rules decide what a re-import actually changes, which is worth knowing before you upload.
The short version
- Import activities upsert into a data extension on the subscriber key you define.
- The All Subscribers list holds global status, and a held or unsubscribed status overrides any data extension.
- Data extension attributes carry arbitrary fields, which is where verification results belong.
- Bounce handling is configurable per send, so retry behavior differs between accounts.
The mistake to avoid
Some addresses come back unresolved, and that is a fact about the receiving server rather than a gap in the check. We label those and never bill for them. What that means, and why roughly 28% of business addresses land there, is set out on our page about catch-all domains.
Questions people ask
How should verification results be used in Marketing Cloud?
As an attribute on the data extension, used in a send filter. That keeps the record intact for other owners while excluding unresolved addresses from a send.
Should I verify before the CRM sync or after?
Ideally at the point the address enters Salesforce. Verifying downstream in Marketing Cloud fixes the send and leaves the CRM holding the same bad data.
What about catch-all domains in enterprise B2B?
They are a large share. Around 28% of a 10,000-email B2B benchmark sat on catch-all domains, which nobody can verify at mailbox level. Treat them as their own segment rather than as valid or invalid.