Octopus "create-release: Release already exists" in CI

octo create-release was rejected because a release with that number already exists for the project. Release numbers are unique per project, so re-running with the same version, or letting two builds pick the same number, collides.

What this error means

octo create-release fails with "A release with the number 1.0.0 already exists for this project" on a re-run or a duplicated pipeline.

octo

octo create-release --project "Web" --version 1.0.0
A release with the number 1.0.0 already exists for this project.

Common causes

The release version was not bumped between runs

A fixed or unchanged --version means a re-run tries to create a release number that already exists.

Two pipelines created the same release number

Concurrent or duplicated builds derived the same version and both tried to create it, so the second one collides.

How to fix it

Derive a unique release version per build

Base --version on the run number or commit so it is unique.
Let Octopus infer package versions or pass them explicitly.
Re-run and confirm the new release number is accepted.

.github/workflows/ci.yml

octo create-release --project "Web" \
  --version "1.0.${{ github.run_number }}" \
  --server "$OCTOPUS_URL" --apiKey "$OCTOPUS_API_KEY"

Make re-runs idempotent

If a pipeline can legitimately re-run for the same version, deploy the existing release instead of creating a new one, or gate creation on whether the release exists.

How to prevent it

Generate unique release versions from CI run metadata.
Avoid hard-coded release numbers in the workflow.
Serialize deploys so two builds do not claim the same number.