What Are the Biggest Risks When Migrating from Marketo or Pardot to HubSpot?

The Three Categories of Migration Risk

Every marketing automation platform migration involves three distinct risk categories. Data integrity risks include losing contacts, corrupting historical engagement data, misaligning custom fields, and breaking list segmentation logic. Workflow continuity risks include gaps in active nurture sequences, broken trigger logic due to platform differences, and sales team workflow disruption during the transition. Attribution risks include losing historical campaign attribution data, breaking UTM tracking continuity, and creating gaps in lead source reporting. The platforms that manage migrations successfully are those that plan for all three categories simultaneously, not sequentially.

Data Mapping: Where Migrations Most Often Break

The most common technical failure in Marketo-to-HubSpot migrations is custom field mapping. Marketo allows fields at both the Lead and Company object level, while HubSpot separates Contacts, Companies, Deals, and custom objects, a fundamentally different data model. Fields that store multiple values in Marketo (multi-select picklists) must be mapped to HubSpot's enumeration properties, which have different formatting requirements. Calculated fields in Marketo that update based on rules must be replicated as HubSpot workflow-updated properties. Before any migration begins, create a full field inventory: source field name, data type, format, current population rate, and the target HubSpot field. Any field with >10% population rate is critical; fields with >50% are essential.

Workflow Recreation: The Most Time-Intensive Phase

Workflow recreation is typically the most labor-intensive part of the migration. Pardot's Engagement Studio and Marketo's Campaign Flow both have different logic paradigms than HubSpot's workflow engine. Before migration, document every active automation program with its trigger conditions, wait steps, branching logic, and exit criteria. Then rebuild each in HubSpot natively, do not attempt to directly translate automation logic, as the underlying event models are different enough that direct translation creates subtle bugs that are hard to detect. A rebuilt HubSpot workflow should be tested with test contact enrollments for 7–14 days before decommissioning the source platform workflow.

Historical Data Preservation Strategy

Historical email engagement data (opens, clicks, bounces) from Marketo and Pardot can be imported into HubSpot as activity timeline events, but only at the contact level, aggregate campaign metrics don't transfer. Before migration, export a complete engagement history for all contacts and store it in a data warehouse or even a Google Sheet as a historical record. For campaign attribution, ensure all historical UTM parameters are preserved in contact properties, HubSpot stores these as "Original Source" and "Original Source Detail" properties, which you should populate from historical campaign data before decommissioning the source platform.

The Migration Timeline That Actually Works

A realistic timeline for a mid-market B2B migration (10,000–50,000 contacts, 20–50 active automation programs): Week 1–2: Full audit and data mapping documentation. Week 3–4: Custom property setup and contact import in HubSpot with deduplication. Week 5–6: Workflow recreation and testing. Week 7: Parallel running, both platforms active, new leads going to HubSpot, existing nurture sequences finishing in the source platform. Week 8: Full cutover with 2 weeks of monitoring. Do not compress this timeline, the parallel running phase is where you catch the workflow gaps that pre-migration testing always misses. Excel's platform migration service includes full data mapping, workflow recreation, and 30-day post-migration monitoring.