diff --git a/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v1beta1/kms_plugin_mock.go b/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v1beta1/kms_plugin_mock.go
index 081d9c1b36c..445bb6a536d 100644
--- a/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v1beta1/kms_plugin_mock.go
+++ b/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v1beta1/kms_plugin_mock.go
@@ -68,6 +68,8 @@ func NewBase64Plugin(t *testing.T, socketPath string) *Base64Plugin {
 		socketPath: socketPath,
 	}
 
+	// Make sure we don't have a leftover socket.
+	_ = os.Remove(socketPath)
 	kmsapi.RegisterKeyManagementServiceServer(server, result)
 	if err := result.start(); err != nil {
 		t.Fatalf("failed to start KMS plugin, err: %v", err)