diff --git a/openbis/source/java/ch/ethz/sis/openbis/generic/server/asapi/v3/context/ProgressStack.java b/openbis/source/java/ch/ethz/sis/openbis/generic/server/asapi/v3/context/ProgressStack.java
index 1e71d6ed5d09e5d1400a9139270295e9c5cc4f9f..e3a1f4ddf81d97f017e2f395c11183d0d68c87fd 100644
--- a/openbis/source/java/ch/ethz/sis/openbis/generic/server/asapi/v3/context/ProgressStack.java
+++ b/openbis/source/java/ch/ethz/sis/openbis/generic/server/asapi/v3/context/ProgressStack.java
@@ -60,8 +60,8 @@ class ProgressStack implements IProgressStack
                 @Override
                 public void remove()
                 {
+                    throw new UnsupportedOperationException();
                 }
-
             };
     }