@@ -76,12 +81,17 @@
   dest_info = {}
   
   dd 'analyzing existing messages...'
-  dest.uid_fetch(dest.uid_search(['ALL']), ['ENVELOPE']).each do |data|
+  uids = dest.uid_search(['ALL'])
+  if uids.length > 0
+    dest.uid_fetch(uids, ['ENVELOPE']).each do |data|
     dest_info[data.attr['ENVELOPE'].message_id] = true
   end
+  end
   
   # Loop through all messages in the source folder.
-  source.uid_fetch(source.uid_search(['ALL']), ['ENVELOPE']).each do |data|
+  uids = source.uid_search(['ALL'])
+  if uids.length > 0
+    source.uid_fetch(uids, ['ENVELOPE']).each do |data|
     mid = data.attr['ENVELOPE'].message_id
 
     # If this message is already in the destination folder, skip it.
@@ -98,6 +108,7 @@
     dest.append(dest_folder, msg.attr['RFC822'], msg.attr['FLAGS'],
         msg.attr['INTERNALDATE'])
   end
+  end
   
   source.close
   dest.close