Index: java/org/apache/catalina/session/StandardManager.java
===================================================================
--- java/org/apache/catalina/session/StandardManager.java	(revision 926567)
+++ java/org/apache/catalina/session/StandardManager.java	(working copy)
@@ -476,6 +476,11 @@
 
         if (log.isDebugEnabled())
             log.debug("Unloading persisted sessions");
+        
+        if (sessions.isEmpty()) {
+            log.debug("No persisted sessions to unload");
+            return; // nothing to do
+        }
 
         // Open an output stream to the specified pathname, if any
         File file = file();