diff --git a/core/src/main/java/org/dcache/nfs/v4/NFS4Client.java b/core/src/main/java/org/dcache/nfs/v4/NFS4Client.java
index 4c3fff304..94740d1c8 100644
--- a/core/src/main/java/org/dcache/nfs/v4/NFS4Client.java
+++ b/core/src/main/java/org/dcache/nfs/v4/NFS4Client.java
@@ -324,7 +324,14 @@ public NFS4State createState(StateOwner stateOwner, NFS4State openState) throws
 
         NFS4State state = new NFS4State(openState, stateOwner, _stateHandler.createStateId(this, _stateIdCounter.incrementAndGet()));
         if (openState != null) {
-            openState.addDisposeListener(s -> state.tryDispose());
+            openState.addDisposeListener(s -> {
+                // remove and dispose derived states.
+                NFS4State nfsState = _clientStates.remove(state.stateid());
+                if (nfsState != null) {
+                    _log.debug("removing derived state {}", nfsState);
+                    nfsState.tryDispose();
+                }
+            });
         }
         _clientStates.put(state.stateid(), state);
         return state;
diff --git a/core/src/main/java/org/dcache/nfs/v4/NFS4State.java b/core/src/main/java/org/dcache/nfs/v4/NFS4State.java
index a44d04a72..e70bc9566 100644
--- a/core/src/main/java/org/dcache/nfs/v4/NFS4State.java
+++ b/core/src/main/java/org/dcache/nfs/v4/NFS4State.java
@@ -19,6 +19,7 @@
  */
 package org.dcache.nfs.v4;
 
+import com.google.common.base.MoreObjects;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -123,4 +124,15 @@ public StateOwner getStateOwner() {
     synchronized public void addDisposeListener(StateDisposeListener disposeListener) {
         _disposeListeners.add(disposeListener);
     }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this.getClass().getSimpleName())
+                .add("stateid", _stateid)
+                .add("open-stateid", _openState == null? null : _openState.stateid())
+                .add("owner", _owner.getRawStateOwner())
+                .add("confirmed", _isConfimed)
+                .omitNullValues()
+                .toString();
+    }
 }