diff --git a/core/includes/errors.inc b/core/includes/errors.inc
index cba08e2..41abccb 100644
--- a/core/includes/errors.inc
+++ b/core/includes/errors.inc
@@ -205,8 +205,11 @@ function _drupal_log_error($error, $fatal = FALSE) {
   }
 
   // Backtrace array is not a valid replacement value for t().
-  $backtrace = $error['backtrace'];
-  unset($error['backtrace']);
+  $backtrace = FALSE;
+  if (isset($error['backtrace'])) {
+    $backtrace = $error['backtrace'];
+    unset($error['backtrace']);
+  }
 
   // When running inside the testing framework, we relay the errors
   // to the tested site by the way of HTTP headers.
@@ -272,7 +275,7 @@ function _drupal_log_error($error, $fatal = FALSE) {
       // Check if verbose error reporting is on.
       $error_level = variable_get('error_level', ERROR_REPORTING_DISPLAY_ALL);
 
-      if ($error_level == ERROR_REPORTING_DISPLAY_VERBOSE) {
+      if ($backtrace && $error_level == ERROR_REPORTING_DISPLAY_VERBOSE) {
         // First trace is the error itself, already contained in the message.
         // While the second trace is the error source and also contained in the
         // message, the message doesn't contain argument values, so we output it