diff --git a/src/main/java/org/caosdb/server/datatype/BooleanDatatype.java b/src/main/java/org/caosdb/server/datatype/BooleanDatatype.java
index 92c3440aeab6ef1cc86426c4e5d2356aef6720aa..366b77937d3dcf020d98c035821bed0aedaadf8d 100644
--- a/src/main/java/org/caosdb/server/datatype/BooleanDatatype.java
+++ b/src/main/java/org/caosdb/server/datatype/BooleanDatatype.java
@@ -32,6 +32,8 @@ public class BooleanDatatype extends AbstractDatatype {
   public SingleValue parseValue(final Object value) throws Message {
     if (value instanceof BooleanValue) {
       return (SingleValue) value;
+    } else if (value instanceof CollectionValue) {
+      throw ServerMessages.DATA_TYPE_DOES_NOT_ACCEPT_COLLECTION_VALUES;
     } else if (value instanceof SingleValue) {
       return parse(((SingleValue) value).toDatabaseString());
     } else {