To clean up duplicate data in Salesforce, measure the problem first, agree on which record wins when two match, merge in batches starting with the highest-value objects, and then turn on duplicate and matching rules so new duplicates are blocked or flagged at entry. Cleanup without prevention only buys a few months.
Where duplicates come from
- Data imports and migrations that did not check for existing records.
- Integrations that create a new record instead of updating an existing one.
- Web forms and marketing tools creating leads for people who are already contacts.
- Users creating records because searching felt slower than typing.
- Inconsistent formats: company names with and without suffixes, phone and email variations.
Measure before you merge
Run duplicate reports on accounts, contacts and leads using a few simple keys, such as email address, normalized company name and website domain. Record the duplicate rate for each object so you can show progress and catch regressions later.
Merge safely
| Step | What to do | Why |
|---|---|---|
| 1. Decide survivorship | Agree which record wins: most recent activity, most complete, or linked to open opportunities | Prevents arguments and lost data mid-merge |
| 2. Back up | Export affected records and related data | Merges cannot be undone |
| 3. Accounts first | Merge duplicate accounts, then their contacts | Contacts and opportunities follow the account |
| 4. Leads last | Convert or merge leads that match existing contacts | Keeps marketing history attached to the right person |
| 5. Check integrations | Confirm connected systems point at the surviving record | Stops the integration from recreating the duplicate |
Salesforce’s standard merge tools handle small batches well. For large volumes, a data-quality tool or a scripted merge with a review step is safer than doing thousands of merges by hand.
Stop them coming back
- Matching rules define what counts as a duplicate for each object.
- Duplicate rules decide whether to block the save or allow it with an alert.
- Validation rules and picklists enforce consistent formats for key fields.
- Integrations should upsert on an external ID rather than insert blindly.
- A monthly duplicate report keeps the rate visible.
Cleanup is often part of a larger project. A demand-generation firm we worked with restored reliable Salesforce and Pardot sync across 145,000+ prospects, and a medical-device company removed 970+ invalid records to get its prospect count back under its license limit.
