diff --git a/cck.install b/cck.install
index 49a2f9b..4a6ab3e 100644
--- a/cck.install
+++ b/cck.install
@@ -93,3 +93,66 @@ function cck_update_7000() {
     db_add_field('cck_field_settings', 'language', $field);
   }
 }
+
+function cck_update_7001(&$sandbox = array()) {
+  $ret = array();
+
+  // Query the existing D6 files table for possible duplicate URIs in D7.
+  if (db_table_exists('files')) {
+    if (!isset($sandbox['progress'])) {
+      $sandbox['progress'] = 0;
+      $sandbox['current_file'] = '';
+      $sandbox['max'] = db_query("SELECT COUNT(f1.fid) FROM {files} f1 WHERE (SELECT count(f2.filepath) FROM {files} f2 WHERE f2.filepath = f1.filepath) > 1 ORDER BY f1.filename")->fetchField();
+    }
+
+    // Update 50 files at a time.
+    $batch_size = 50;
+    $query = "SELECT f1.fid, f1.filename, f1.filepath FROM {files} f1 WHERE (SELECT count(f2.filepath) FROM {files} f2 WHERE f2.filepath = f1.filepath) > 1 ORDER BY f1.filename";
+    $result = db_query_range($query, $sandbox['current_file'], $batch_size);
+    $last_file = '';
+
+    foreach ($result as $record) {
+      if ($record->filepath == $last_file) {
+        // Log an error if the file copy destination is not writable.
+        $directory = str_replace('/' . $old_file, '', $record->filepath);
+        if (!file_prepare_directory($directory, FILE_CREATE_DIRECTORY)) {
+          watchdog('cck', 'The directory %directory could not be created or is not accessible.', array('%directory' => $directory));
+        }
+        else {
+          // Log an error if the destination does not contain a valid stream.
+          $destination = variable_get('file_default_scheme', 'public') . '://';
+          $destination_scheme = file_uri_scheme($destination);
+          if (!$destination_scheme || !file_stream_wrapper_valid_scheme($destination_scheme)) {
+            watchdog('cck', 'The file could not be copied, because the destination %destination is invalid.', array('%destination' => $destination), 'error');
+          }
+          else {
+            // Duplicate file via copy.
+            $new_path = str_replace("public://", "", file_destination($destination . $record->filepath, FILE_EXISTS_RENAME));
+            $saved_filepath = file_unmanaged_copy($record->filepath, $new_path, FILE_EXISTS_RENAME);
+
+            // Update the database to use the new filename.
+            if ($saved_filepath) {
+              $saved_filepath_base = basename($saved_filepath);
+              $num_updated = db_update('files')
+                ->fields(array(
+                  'filename' => $saved_filepath_base,
+                  'filepath' => $saved_filepath,
+                ))
+                ->condition('fid', $record->fid, '=')
+                ->execute();
+              drupal_set_message("Updated file: fid: $record->fid, $record->filename to $saved_filepath_base");
+            }
+          }
+        }
+      }
+      $last_file = strtolower($record->filepath);
+
+      $sandbox['current_file'] = $record->filepath;
+    }
+
+    $sandbox['progress']++;
+    $sandbox['#finished'] = empty($sandbox['max']) ? 1 : ($sandbox['progress'] / $sandbox['max']);
+  }
+
+  return $ret;
+}