diff --git a/classes/db/DB.class.php b/classes/db/DB.class.php
index dac2504f9..1db0cf0c1 100644
--- a/classes/db/DB.class.php
+++ b/classes/db/DB.class.php
@@ -459,7 +459,7 @@ class DB
 					$buff[] = '<?php exit(); ?>';
 				}
 				$buff[] = print_r($log, TRUE);
-				@file_put_contents($log_file, implode("\n", $buff) . "\n\n", FILE_APPEND);
+				@file_put_contents($log_file, implode("\n", $buff) . "\n\n", FILE_APPEND|LOCK_EX);
 			}
 		}
 		else
@@ -480,7 +480,7 @@ class DB
 
 			$buff .= sprintf("%s\t%s\n\t%0.6f sec\tquery_id:%s\n\n", date("Y-m-d H:i"), $this->query, $elapsed_time, $this->query_id);
 
-			@file_put_contents($log_file, $buff, FILE_APPEND);
+			@file_put_contents($log_file, $buff, FILE_APPEND|LOCK_EX);
 		}
 	}
 
diff --git a/classes/display/DisplayHandler.class.php b/classes/display/DisplayHandler.class.php
index 40589a843..973cbdf5b 100644
--- a/classes/display/DisplayHandler.class.php
+++ b/classes/display/DisplayHandler.class.php
@@ -297,7 +297,7 @@ class DisplayHandler extends Handler
 				$buff = str_repeat('=', 40) . "\n" . $buff . str_repeat('-', 40);
 				$buff = "\n<?php\n/*" . $buff . "*/\n?>\n";
 
-				if (!@file_put_contents($debug_file, $buff, FILE_APPEND))
+				if (!@file_put_contents($debug_file, $buff, FILE_APPEND|LOCK_EX))
 				{
 					return;
 				}
diff --git a/classes/file/FileHandler.class.php b/classes/file/FileHandler.class.php
index 02ccff9ec..1ca76df32 100644
--- a/classes/file/FileHandler.class.php
+++ b/classes/file/FileHandler.class.php
@@ -176,7 +176,7 @@ class FileHandler
 			$flags = 0;
 		}
 
-		@file_put_contents($file_name, $buff, $flags);
+		@file_put_contents($file_name, $buff, $flags|LOCK_EX);
 		@chmod($file_name, 0644);
 	}
 
diff --git a/classes/security/htmlpurifier/library/HTMLPurifier/DefinitionCache/Serializer.php b/classes/security/htmlpurifier/library/HTMLPurifier/DefinitionCache/Serializer.php
index 73d5e90a6..8afb3fe64 100644
--- a/classes/security/htmlpurifier/library/HTMLPurifier/DefinitionCache/Serializer.php
+++ b/classes/security/htmlpurifier/library/HTMLPurifier/DefinitionCache/Serializer.php
@@ -101,7 +101,7 @@ class HTMLPurifier_DefinitionCache_Serializer extends
      * @return Number of bytes written if success, or false if failure.
      */
     private function _write($file, $data, $config) {
-        $result = file_put_contents($file, $data);
+        $result = file_put_contents($file, $data, LOCK_EX);
         if ($result !== false) {
             // set permissions of the new file (no execute)
             $chmod = $config->get('Cache.SerializerPermissions');
diff --git a/classes/security/htmlpurifier/library/HTMLPurifier/URIScheme/data.php b/classes/security/htmlpurifier/library/HTMLPurifier/URIScheme/data.php
index a5c43989e..a6a9bdcdd 100644
--- a/classes/security/htmlpurifier/library/HTMLPurifier/URIScheme/data.php
+++ b/classes/security/htmlpurifier/library/HTMLPurifier/URIScheme/data.php
@@ -61,7 +61,7 @@ class HTMLPurifier_URIScheme_data extends HTMLPurifier_URIScheme {
         // XXX probably want to refactor this into a general mechanism
         // for filtering arbitrary content types
         $file = tempnam("/tmp", "");
-        file_put_contents($file, $raw_data);
+        file_put_contents($file, $raw_data, LOCK_EX);
         if (function_exists('exif_imagetype')) {
             $image_code = exif_imagetype($file);
         } elseif (function_exists('getimagesize')) {
diff --git a/classes/validator/Validator.class.php b/classes/validator/Validator.class.php
index d16eebb12..54aa68e08 100644
--- a/classes/validator/Validator.class.php
+++ b/classes/validator/Validator.class.php
@@ -682,7 +682,7 @@ class Validator
 			return FALSE;
 		}
 
-		@file_put_contents($filepath, $content);
+		@file_put_contents($filepath, $content, LOCK_EX);
 
 		return $filepath;
 	}
diff --git a/config/func.inc.php b/config/func.inc.php
index a3da73c79..b37a01df1 100644
--- a/config/func.inc.php
+++ b/config/func.inc.php
@@ -801,7 +801,7 @@ function debugPrint($debug_output = NULL, $display_option = TRUE, $file = '_debu
 		}
 		$debug_output = "\n<?php\n/*" . $debug_output . "*/\n?>\n";
 
-		@file_put_contents($debug_file, $debug_output, FILE_APPEND);
+		@file_put_contents($debug_file, $debug_output, FILE_APPEND|LOCK_EX);
 	}
 }
 
diff --git a/libs/phpmailer/phpmailer.php b/libs/phpmailer/phpmailer.php
index b809939dd..c36f7c9d8 100644
--- a/libs/phpmailer/phpmailer.php
+++ b/libs/phpmailer/phpmailer.php
@@ -1234,7 +1234,7 @@ class PHPMailer {
     } else if ($this->sign_key_file) {
       try {
         $file = tempnam('', 'mail');
-        file_put_contents($file, $body); //TODO check this worked
+        file_put_contents($file, $body, LOCK_EX); //TODO check this worked
       $signed = tempnam("", "signed");
         if (@openssl_pkcs7_sign($file, $signed, "file://".$this->sign_cert_file, array("file://".$this->sign_key_file, $this->sign_key_pass), NULL)) {
           @unlink($file);
diff --git a/modules/module/module.admin.controller.php b/modules/module/module.admin.controller.php
index 57c3222b0..55cf1b9c5 100644
--- a/modules/module/module.admin.controller.php
+++ b/modules/module/module.admin.controller.php
@@ -899,7 +899,7 @@ class moduleAdminController extends module
 			{
 				$str = sprintf('$lang[\'%s\'] = \'%s\';', $code, addcslashes($value, "'"));
 			}
-			if (!@file_put_contents(sprintf('%s/%d.%s.php', $cache_path, $args->site_srl, $langCode), $str))
+			if (!@file_put_contents(sprintf('%s/%d.%s.php', $cache_path, $args->site_srl, $langCode), $str, LOCK_EX))
 			{
 				return;
 			}
diff --git a/modules/point/point.admin.controller.php b/modules/point/point.admin.controller.php
index 8cef35414..c021335f3 100644
--- a/modules/point/point.admin.controller.php
+++ b/modules/point/point.admin.controller.php
@@ -287,7 +287,7 @@ class pointAdminController extends point
 			$str .= $key.','.$val."\r\n";
 		}
 
-		@file_put_contents('./files/cache/pointRecal.txt', $str);
+		@file_put_contents('./files/cache/pointRecal.txt', $str, LOCK_EX);
 
 		$this->add('total', count($member));
 		$this->add('position', 0);
diff --git a/tools/minify/minify.php b/tools/minify/minify.php
index 37204776f..6c493f5d5 100755
--- a/tools/minify/minify.php
+++ b/tools/minify/minify.php
@@ -86,7 +86,7 @@ function execute($dir) {
 			$content = JSMinPlus::minify($content);
 		}
 
-		file_put_contents($target, $copyright.$content);
+		file_put_contents($target, $copyright.$content, LOCK_EX);
 
 		echo '.';
 	}
@@ -107,7 +107,7 @@ function execute($dir) {
 		$target  = preg_replace('@\.css$@', '.min.css', $file);
 		$content = file_get_contents($file);
 
-		file_put_contents($target, $copyright.$oCSSmin->run($content));
+		file_put_contents($target, $copyright.$oCSSmin->run($content), LOCK_EX);
 		echo '.';
 	}
 	echo " Done\n";
@@ -167,7 +167,7 @@ function merge($files, $target, $base_dir) {
 	if ($body) {
 		$file_count = count($files);
 		echo "  Merging {$file_count} files to create {$target} file...";
-		file_put_contents($base_dir.$target, $body);
+		file_put_contents($base_dir.$target, $body, LOCK_EX);
 		echo " Done\n";
 	}
 }