diff --git a/src/main/java/org/lisapark/octopus/repository/db4o/OctopusDb4oRepository.java b/src/main/java/org/lisapark/octopus/repository/db4o/OctopusDb4oRepository.java
index 46b8556..28baee9 100644
--- a/src/main/java/org/lisapark/octopus/repository/db4o/OctopusDb4oRepository.java
+++ b/src/main/java/org/lisapark/octopus/repository/db4o/OctopusDb4oRepository.java
@@ -120,6 +120,9 @@ public boolean match(ProcessingModel model) {
             });
         } catch (Db4oException e) {
             throw new RepositoryException(e);
+        } catch (IllegalStateException e) {
+            // this is thrown if the class structure is incompatible with the current structure
+            throw new RepositoryException(e);
         }
     }
 }