diff --git a/includes/startup.inc b/includes/startup.inc
index 693fede..fedccbf 100644
--- a/includes/startup.inc
+++ b/includes/startup.inc
@@ -326,8 +326,8 @@ function drush_startup($argv) {
     }
   }
 
-  // Always use pcntl_exec if it exists.
-  $use_pcntl_exec = function_exists("pcntl_exec");
+  // https://github.com/drush-ops/drush/issues/2065
+  $use_pcntl_exec = FALSE;
 
   // If we have posix_getppid, then pass in the shell pid so
   // that 'site-set' et. al. can work correctly.