How to Avoid a Duplicate Disaster When Migrating to HubSpot

Migrating to HubSpot is exciting — new workflows, automation, cleaner data… right?
Until the first week after go-live, when:

💬 Sales sees two of the same company.
💬 Marketing emails the same contact twice.
💬 Support can’t tell which record is the right one.

It happens all the time — and the result is almost always the same:
people stop trusting the CRM.

Bad data kills adoption faster than a slow internet connection.
So if you’re planning (or in the middle of) a migration to HubSpot, here’s how to keep your data — and your team’s trust — intact.

1️⃣ Import Original Record IDs

Your first rule: never lose the original record IDs from your source systems.

Those IDs are your anchor points for everything that happens after go-live — reimports, updates, troubleshooting, or mapping associations like activities and deals.

Why it matters:

Without the original ID, HubSpot can’t always tell which imported record belongs to which entity in your old system. That’s when duplicate creation starts to snowball.

Best practice:

• Create a custom property in HubSpot for each source system (e.g., Salesforce Record ID, ERP Customer ID, Freshsales Contact ID).

• Always include it during your import process.

• Use these IDs as your unique identifiers for future updates or bulk reimports.

This simple step can save you hours of manual cleanup later.

2️⃣ Avoid Premature Merges

This is one of the biggest mistakes during migrations.

You import data from multiple systems — and it’s tempting to start merging right away to “clean things up.”
Don’t.

Why it matters:

If you merge too early, you’ll break critical links that depend on your original system’s record IDs (like activities, notes, or associations). Once they’re gone, you can’t reattach them.

What to do instead:

• Keep records from each system separate until all related data (activities, deals, tickets, etc.) is imported and validated.

• Use a naming or tagging convention (like Source = Salesforce or Source = ERP) so you can easily filter and manage each dataset.

• Only merge once you’ve confirmed that associations are in place and everything has synced correctly.

Think of it like moving into a new house — unpack everything first, then start rearranging the furniture.

3️⃣ Create Custom Deduplication Rules

Every business has unique data patterns — so your deduplication logic should match that reality.

Instead of relying only on HubSpot’s default rules (which primarily match on email or domain), create custom rules that reflect your actual data structure.

Examples:

• Contacts: First name + last name + phone number

• Companies: Company name + VAT number or Company name + country

• Deals: Deal name + associated company

Then, determine which record should be treated as the primary record.
Usually, you’ll want to merge into the imported record (not overwrite it) — that’s the one tied to your original system.

How to automate this:

Koalify 🐨 makes this process easy.
You can create flexible, rule-based deduplication workflows that automatically merge duplicates based on your chosen criteria — safely, without guesswork.

Koalify’s approach helps you avoid merging unique records too early, and gives you visibility into what’s being merged, when, and why.

4️⃣ Plan a Cleanup Phase

Data migrations aren’t one-and-done — they’re a process.

Even if you do everything right, there will still be outliers, old records, and weird one-off cases. That’s completely normal.

Best practice:

• Allow at least a one- to two-week “cooldown” period after your first import.

• Let data sync, workflows run, and users start interacting with the CRM.

• Then, run your first major deduplication or cleanup round.

By waiting, you ensure that:

• New data has settled (and new duplicates are visible).

• You can see patterns of recurring errors before automating merges.

• Your cleanup won’t conflict with other syncs or workflows running in parallel.

A calm cleanup beats a chaotic one every time.

5️⃣ Keep Everyone Informed

Data quality isn’t just an ops problem — it’s a trust problem.

If your sales team sees duplicate accounts or missing contacts with no context, they’ll immediately lose confidence in the system. And once that happens, adoption plummets.

What to do:

• Be transparent during migration. Tell teams what’s happening and when.

• Explain that duplicates may appear temporarily — and share the cleanup plan.

• Give visibility: dashboards, reports, or even Slack updates to track progress.

When users know what’s going on, they stay confident — and patient.

🧩 Final Thoughts

Migrating to HubSpot successfully isn’t just about moving data — it’s about building trust in your new CRM.

That means thinking beyond import files and workflows:
✅ Retain source IDs.
✅ Merge smartly (not early).
✅ Automate safely with custom rules.
✅ Let your data breathe before cleanup.
✅ Keep everyone in the loop.

Do this right, and your team won’t just use HubSpot — they’ll trust it.

And when that happens, your CRM becomes what it was always meant to be:
a single source of truth.