diff --git a/whelk-core/src/main/groovy/whelk/converter/marc/ContributionByRoleStep.groovy b/whelk-core/src/main/groovy/whelk/converter/marc/ContributionByRoleStep.groovy
index c8a6c17983..64312e41b1 100644
--- a/whelk-core/src/main/groovy/whelk/converter/marc/ContributionByRoleStep.groovy
+++ b/whelk-core/src/main/groovy/whelk/converter/marc/ContributionByRoleStep.groovy
@@ -39,6 +39,10 @@ class ContributionByRoleStep extends MarcFramePostProcStepBase {
     }
 
     void modify(Map record, Map thing) {
+        if (!relatorLinker || !instanceRelators) {
+            log.error("Conversion failed: Missing required resources")
+            return
+        }
         moveRoles(thing)
     }