White screen of death: Fatal error: Allowed memory size of X bytes exhausted
I know this may be late, but it helped me. Most times a module causes WSOD, I couldn't just disable modules to test which it was, since I may have lost data in the process. What I did was to temporarily edit this function in module.inc, in the core includes directory

function module_invoke_all($hook) {
  $args = func_get_args();
  // Remove $hook from the arguments.
  unset($args[0]);
  $return = array();
  foreach (module_implements($hook) as $module) {

        print "Starting loading $module &lt;br /&gt;";

        $function = $module . '_' . $hook;
        if (function_exists($function)) {
          $result = call_user_func_array($function, $args);
          if (isset($result) &amp;&amp; is_array($result)) {
            $return = array_merge_recursive($return, $result);
          }
          elseif (isset($result)) {
            $return[] = $result;
          }
        }

        print "Finished loading $module &lt;br /&gt;";

  }

  return $return;
}


And I added those 2 print statements in the code above, then refresh the page, the module which didn't reach the "Finish loading $module" statement is the one with the problem... it was devel in my case.

After finding the module, you can go into the system table and look for that module, set it's status = 0 and bootstrap = 0 or run the query:

UPDATE system SET status = 0, bootstrap = 0 WHERE name = 'module_name' LIMIT 1


Reference: Debugging Drupal White Screen of Death (WSOD)