Sync Email as Salesforce Activity: How It Works After the EAC on Core Rebuild

Key Takeaways

Sync Email as Salesforce Activity is an Einstein Activity Capture setting. It saves eligible sent and received emails as native Salesforce EmailMessage and Task records. The records pull from Gmail or Outlook inboxes and live on the Salesforce platform. They work with the Activity Timeline, reports, sharing rules, APIs, and Flow automation.

• After Summer '25, Einstein Activity Capture was rebuilt on Salesforce Core. Migration started in new sandboxes on 26 June 2025 and in production orgs from 18 July 2025.
• Full capture stores the subject and body. Header-Only Capture keeps participants, date, and time only.
• EAC does not capture attachments, opens, or clicks.
• Salesforce can sync up to 180 days of historical email from the date the feature is enabled.
• Pre-Summer '25 EAC orgs need a Salesforce Support ticket to migrate. Once the migration starts, it cannot be reversed.

Ask your reps how many customer emails they logged in Salesforce this month and how many they actually sent. The two numbers are never close, and that gap is where deals fall through the cracks.

Sync Email as Salesforce Activity closes it. Einstein Activity Capture pulls every eligible sent and received email into Salesforce. Each one becomes a native EmailMessage and Task record, linked to the right Lead, Contact, Account, and Opportunity.

Once that runs, your Activity Timeline reflects reality so reps stop retyping and managers stop guessing. When someone leaves, their customer conversations stay in the CRM.

By the end of this guide, you will know what to enable and what to skip. You will also know where to check when the capture misses. And how to move a legacy EAC org onto the new experience.

What is Sync Email as Salesforce Activity?

Sync Email as Salesforce Activity is an Einstein Activity Capture (EAC) setting. It stores eligible sent and received customer emails as native Salesforce EmailMessage and Task records. The Activities: Match Email to Records Flow links each email to the right Lead, Contact, Account, and Opportunity.

Captured emails are native records, so they appear on the Activity Timeline. They also work with reports, sharing rules, APIs, triggers, and Flow automation. Admins get the same control they have over any other activity.

What changed in the Summer '25 EAC on Core rebuild

Einstein Activity Capture was rebuilt on Salesforce Core in Summer '25. Captured emails no longer sit in a separate 6-month layer. They now live directly on the platform as native records. Migration started in new sandboxes on 26 June 2025 and in production orgs from 18 July 2025.

The rebuild changes three things for admins.

• Retention: Older EAC kept email data in AWS for six months only. Native records follow your Salesforce data retention rules instead. That makes captured emails safe for compliance and long-term reporting.
• Access: Captured emails now respect standard activity sharing, role hierarchy, and task ownership. Any user with record access can find, report on, or automate against them.
• Coverage: Reports, Flow, triggers, and APIs work on captured emails the same way they work on manual activities. There is no more separate capture layer to work around.

What EAC captures and what it does not

Einstein Activity Capture (EAC) captures the sender, recipients, date, time, subject, and body of eligible sent and received emails. EAC does not capture attachments, mass sends, opens, or clicks. Messages sync from a connected Gmail or Outlook inbox.

How much of the email content actually lands in Salesforce depends on a capture setting. Admins choose between full capture and Header-Only Capture at the org and user level.

Full capture vs Header-Only Capture

Full capture stores the complete email, including subject and body.Header-Only Capture stores participants, date, and time, but leaves the subject and body out.

Emails sent through the Salesforce Email Composer are always captured in full, regardless of the Header-Only setting. That is the one place the admin default does not apply.

Troubleshooting: why emails do not sync or match to records

The four common causes are an unauthenticated inbox, a missing Contact, an excluded address, or an incomplete initial sync. When one hits, the captured email exists inside EAC but does not appear where an admin expects. Each has a settings-level fix that runs faster than a Flow rebuild.

• Unauthenticated or aliased inbox: EAC does not authenticate email aliases as separate connected accounts. ForOutlook and Salesforce integrations, the Salesforce User email, primary SMTP, and user principal name must match.
• Missing or duplicate Contact: The Match Email to Records Flow needs a clean address on a User, Lead, or Contact. Duplicates split ownership and send the email to the wrong record.
• Excluded email address: Check the EAC exclusion list. Any address on it is skipped, whether sender or recipient.
• Initial sync is still running: The first sync after connecting an inbox can take up to 24 hours. Emails sent within that window may not appear on a related record.

Header-Only Capture also blocks Einstein generative AI features from using the email body. Teams that need AI summaries or send-time suggestions should weigh privacy against AI coverage.

How the Match Email to Records Flow works

The Match Email to Records Flow compares sender, recipient, and CC addresses against existing Users, Leads, and Contacts. It then links the email to related Accounts and Opportunities on the Activity Timeline. The Flow runs automatically on every email Einstein Activity Capture (EAC) syncs.

The Flow runs four steps in order:

1. Check the sender, recipient, and CC addresses on the incoming email.
2. Match those addresses to Salesforce Users, Leads, and Contacts.
3. Find related Accounts and Opportunities through those matches.
4. Add the matched records to the EmailMessage and associated Task.

Match quality depends on clean email fields. Missing addresses, duplicate Contacts, or outdated records can send the activity to the wrong Lead or leave it unlinked.

When Salesforce finds no match and how to fix it

When the Flow finds no match, Salesforce keeps any valid links and leaves the unknown addresses unmatched. The captured email still exists in EAC. It does not appear on the expected Lead, Contact, Account, or Opportunity timeline. The fix is upstream: clean the CRM data or customize the matching rules.

Four moves catch most of these cases:

• Clean duplicate Leads and Contacts. Two Contacts with the same address split the match and confuse ownership.
• Review the EAC exclusion list. Removing an address from the list makes it eligible again.
• Enable automatic Contact creation. This creates a Contact from a new email address, so the Flow has a target.
• Customize the standard Flow. Admins can copy and edit it to check custom email fields or adjust which Opportunity gets the primary link.

Salesforce activities can link to several people but only one primary business record. That record is the "What", such as an Account or Opportunity, while people are the "Who" links. Pick which business record deserves the "What" slot before editing the Flow.

How to migrate a pre-existing EAC org to EAC on Core

Existing Einstein Activity Capture (EAC) orgs migrate to EAC on Core through four admin steps plus a Salesforce-assigned date. The steps are a Support ticket, an EAC onboarding call, a consent review, and a pause on dependent syncs. Salesforce runs the update on its assigned date, and the process cannot be reversed once it begins.

Run the four admin steps in order:

1. Log a Salesforce Support ticket. Request the update from legacy EAC to Sync Email as Salesforce Activity on EAC on Core. Cite theSummer '25 release notes if the support agent needs context.
2. Book the EAC onboarding call. Salesforce runs a short review of your current EAC setup, connected inboxes, and users. Bring the list of orgs, admins, and any custom Flow tied to EmailMessage or Task.
3. Confirm consent and sharing settings. The new experience makes captured emails follow standard activity sharing rules. Review the roles and hierarchies that will now see previously private EAC data.
4. Pause dependent syncs and integrations. Any middleware or third-party tool reading legacy EAC data should pause until the migration completes. Otherwise, it can double-write records or lose links.

After step 4, Salesforce migrates on its assigned date and notifies admins by email when it finishes.

What to verify after migration

After migration, verify five things: user send and receive, timeline records, flow behavior, report volumes, and sharing visibility. Run each check within the first week to catch issues while Salesforce Support still has the migration ticket open. Most failures trace back to a settings gap, which support can resolve without rerunning the migration.

Here is what each check covers:

1. User send and receive. Confirm reps can send from Gmail or Outlook and see the message land on the right record.
2. Activity Timeline records. Captured emails should appear as native EmailMessage entries. "Captured by EAC" placeholders mean the migration is stuck.
3. Flow and trigger behavior. Any Flow or Apex trigger firing on EmailMessage or Task should still run without errors.
4. Report volumes. Custom activity reports should return counts within 5 to 10 percent of pre-migration baselines.
5. Sharing and visibility. Check that emails linked to shared Accounts and Opportunities show up for the intended roles.

Reports, storage, and Data Cloud archiving for synced emails

Captured emails appear in Salesforce reports, count against data storage, and can be archived to Data Cloud. Each behavior works because captured emails are native EmailMessage and Task records. This model replaced the 6-month AWS retention layer that pre-Summer '25 EAC orgs used.

Activity sharing rules still control who sees each captured email. Task ownership and role hierarchy decide record access.

What to report on

Salesforce Activity reports and custom EmailMessage reports both show captured email data. Standard Activity reports include emails alongside calls, meetings, tasks, and manually logged messages. Custom EmailMessage reports give an email-focused view. Common cuts include message volume per rep, response times by Account, and coverage on named Opportunities.

Activity reports show communication volume. They do not showemail metrics like opens or clicks.

Storage limits and the Data Cloud archive window

Captured emails count toward Salesforce data storage the same way any EmailMessage and Task record does. Salesforce provides a Data Cloud archive path for captured email data that has aged past active reporting needs. Data Cloud keeps the records searchable and reportable without loading the transactional platform. Historical sync at enablement pulls up to 180 days of past email.

Before expanding automatic capture, review four numbers.

• How many users will connect their inboxes.
• How much customer email each user handles.
• How long records must remain in the active platform.
• When older activity should move to Data Cloud.

Using EAC-synced emails with Agentforce triage

Agentforce reads Sync Email as Salesforce Activity records directly and can triage inbound customer email. An AI Agent classifies each captured message by intent and summarizes the thread on the linked Account or Opportunity. It then drafts a reply or routes the case to the right owner. Full capture is required, since Header-Only strips the body content the agent needs.

Two practical use cases map cleanly to Salesforce sales and service teams.

• Inbox triage on cases. Agentforce reads captured emails on Contact records and tags the intent. It links the message to the right Case owner without a rep opening the inbox.
• Deal summarization on Opportunities. The AI Agent reads all captured emails on an Opportunity and updates a rolling summary on the record. Any rep or manager can see the current state without scrolling the Timeline.

The Data Cloud archive expands the context. Agents can query older captured emails for pattern detection across the full customer history.

Track opens, clicks, and campaigns inside Salesforce

Sync Email as Salesforce Activity confirms an email was sent. It does not show whether the recipient opened it, clicked a link, or ignored the thread. Teams that need opens, clicks, bulk sends, or engagement automation need a Salesforce-native tool alongside EAC.

MassMailer runs entirely inside Salesforce. It sends bulk campaigns from Leads, Contacts, and Reports without hitting Gmail or Outlook send limits. It tracks opens, clicks, and bounces at the record level. Flow automation runs on engagement events like link clicks or unsubscribes.

So, EAC keeps a record of every one-to-one conversation. MassMailer adds the campaign layer, engagement data, and behavior-driven automation on top.

Book a MassMailer demo to see both working together in your Salesforce org.