The specified lookup is ambiguous. Lookup must return at most one row for the specified lookup condition

The specified lookup is ambiguous. Lookup must return at most one row for the specified lookup condition

This error occurs when a Lookup operation returns multiple matching records for the specified condition. Lookups are designed to find and act on only one record. When that’s not possible, this error is triggered.

Possible solutions are blow:

1. Use "First Match" Option
Enable the "Use first match when multiple results" setting to proceed with the first matching record found.


Use case: You're importing customer data and matching records based on the email address. But some customers share the same email (e.g., shared support inboxes). If uniqueness isn’t critical, you can enable this option to proceed with the first match, for example, to just retrieve a contact ID or status.

2. Use Different Lookup Key Columns
Review your Lookup condition. Instead of relying on a single column, try using a more specific one that guarantees a unique match.

Use case: You're using Product Name to look up product data, but multiple products might share the same name (e.g., "T-shirt"). Try using Product SKU or Product ID instead, these are more likely to uniquely identify the record.

3. Use Composite Lookup Keys
Add one or more set of columns to your existing lookup keys to form a composite key that narrows down to a single row.


Use case: In a multi-branch company, you’re looking up employees by Employee ID, but IDs are reused across branches. Combine Employee ID and Branch Code in your Lookup, this makes the match unique within the context of each branch.

Best Practices:​​​​​
  • Always aim to construct Lookup conditions that return exactly one matching record.
  • Composite keys are particularly useful when dealing with hierarchical data (e.g., same names or IDs across different regions, teams, or business units).
  • Avoid using non-unique columns like "Name" or "Status" alone for Lookups.
Please refer to the Lookup article for more details.