diff --git a/source/de/anomic/plasma/plasmaHTCache.java b/source/de/anomic/plasma/plasmaHTCache.java
index 99b3bf474..331410332 100644
--- a/source/de/anomic/plasma/plasmaHTCache.java
+++ b/source/de/anomic/plasma/plasmaHTCache.java
@@ -328,6 +328,7 @@ public final class plasmaHTCache {
 
     private void cleanupDoIt(long newCacheSize) {
         File obj;
+        synchronized (cacheAge) {
         Iterator iter = this.cacheAge.keySet().iterator();
         while (iter.hasNext() && this.curCacheSize >= newCacheSize) {
             Object key = iter.next();
@@ -349,6 +350,7 @@ public final class plasmaHTCache {
             }
             iter.remove();
         }
+        }
     }
 
     private void cleanup() {