¬ just serendipity 🍀 (not just serendipity)

If you experience the title error message in ArgoCD (e.g. via its web UI and/or in pod logs), it’s related to argo-cd#5068. The full error message is:

Unable to load data: cache: key is missing

As I commented in the bug, here’s how to fix it:

The following workaround sufficed for me: kubectl delete pod -n argocd argocd-application-controller-0.

Initially I ran kubectl rollout restart deployment -n argocd argocd-application-controller but it didn’t work.

In my experience, this error only happens once, ephemerally, during ArgoCD bootstrapping. Once fixed it does not reoccur.

Update(2025-06-06): This error reoccurs intermittently 🤷.

Another potential workaround is to disable redis / caching altogether, as ArgoCD can fully operate without it, but I wouldn’t recommend that.

See also: #18503.