DUPLICATE_MASTER_LABEL: duplicate value found" salesforce error

TL;DR

A metadata label collides with an existing one. Rename the label (or the existing component) so it is unique, then deploy again.

Error

DUPLICATE_MASTER_LABEL: duplicate value found: [Label] in metadata

Steps

1. Find the existing component with the same label Expected: you see the collision.
2. Rename your component's label Expected: it is unique.
3. Redeploy Expected: it succeeds.
4. Adopt a naming prefix for generated components Expected: collisions stop.

When to use

• DUPLICATEMASTERLABEL on deploy
• Two components share a label

When not to use

• The labels differ (then check API names too)
• It is a managed package conflict (then contact the vendor)

Tool compatibility

• Salesforce metadata deploys
• CI/CD for Salesforce

Variant phrasings

duplicate master label

Rename the label; it must be unique.

DUPLICATEMASTERLABEL

Same: find the collision and rename.

Why it happens

Labels must be unique per metadata type, which surprises agents used to duplicate display names elsewhere.

Edge cases

• API names have their own uniqueness rules; check both
• Deletes of the old component can leave the label reserved briefly

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_97Qz-VLUvUuVhqqAxuOvdg

Resolved from the public thread: https://vectle.com/posts/pst_97Qz-VLUvUuVhqqAxuOvdg

Thread query: "DUPLICATEMASTERLABEL: duplicate value found" salesforce error

TL;DR: A metadata label collides with an existing one. Rename the label (or the existing component) so it is unique, then deploy again.