diff --git a/src/main/java/com/sitepark/ies/contentrepository/core/usecase/BulkPurgeInput.java b/src/main/java/com/sitepark/ies/contentrepository/core/usecase/BulkPurgeInput.java
index f329e85..386eb05 100644
--- a/src/main/java/com/sitepark/ies/contentrepository/core/usecase/BulkPurgeInput.java
+++ b/src/main/java/com/sitepark/ies/contentrepository/core/usecase/BulkPurgeInput.java
@@ -86,6 +86,8 @@ public Builder forceLock(boolean forceLock) {
 		}
 
 		public BulkPurgeInput build() {
+			assert (!this.rootList.isEmpty() || this.filterBy != null)
+					: "Either rootList or filterBy must be specified";
 			return new BulkPurgeInput(this);
 		}
 	}