diff --git a/search2/documentProcessor/documentProcessor.inc.php b/search2/documentProcessor/documentProcessor.inc.php
index 65a72f3..f048840 100644
--- a/search2/documentProcessor/documentProcessor.inc.php
+++ b/search2/documentProcessor/documentProcessor.inc.php
@@ -144,6 +144,16 @@ class DocumentProcessor
         global $default;
         $default->log->debug('documentProcessor: starting');
 
+        // Check for lock file to ensure processor is not currently running
+        $cacheDir = $default->cacheDirectory;
+        $lockFile = $cacheDir . DIRECTORY_SEPARATOR . 'document_processor.lock';
+
+        if(file_exists($lockFile)){
+            // lock file exists, exit
+            $default->log->debug('documentProcessor: stopping, lock file in place '.$lockFile);
+            return ;
+        }
+
         if($default->enableIndexing){
             // Setup indexing - load extractors, run diagnostics
             if($this->indexer->preIndexingSetup() === false){
@@ -160,6 +170,10 @@ class DocumentProcessor
             return ;
         }
 
+        // indexing starting - create lock file
+        touch($lockFile);
+
+
         // Process queue
         foreach($queue as $item){
 
@@ -198,6 +212,11 @@ class DocumentProcessor
         // update the indexer statistics
         $this->indexer->updateIndexStats();
 
+        // Remove lock file to indicate processing has completed
+        if(file_exists($lockFile)){
+            @unlink($lockFile);
+        }
+
         $default->log->debug('documentProcessor: stopping');
     }