diff --git a/_init.php b/_init.php
index 74a0ef4..b9df621 100644
--- a/_init.php
+++ b/_init.php
@@ -17,5 +17,4 @@ if (!defined('DC_RC_PATH')) {
 class initActivityReport
 {
     public const ACTIVITY_TABLE_NAME = 'activity';
-    public const CACHE_DIR_NAME      = 'activityreport';
 }
diff --git a/src/ActivityReport.php b/src/ActivityReport.php
index e92746a..7ae3a40 100644
--- a/src/ActivityReport.php
+++ b/src/ActivityReport.php
@@ -61,8 +61,8 @@ class ActivityReport
     /** @var    ActivityReport  $instance   ActivityReport instance */
     private static $instance;
 
-    /** @var null|resource  $lock   File lock for update */
-    private $lock = null;
+    /** @var null|string  $lock   File lock for update */
+    private static $lock = null;
 
     /**
      * Constructor sets activity main type.
@@ -495,75 +495,49 @@ class ActivityReport
     }
 
     /**
-     * Lock update.
-     *
      * Lock a file to see if an update is ongoing.
      *
-     * @return  bool    The lock success
+     * @return  bool    True if file is locked
      */
     public function lockUpdate(): bool
     {
         try {
-            # Need flock function
-            if (!function_exists('flock')) {
-                throw new Exception("Can't call php function named flock");
-            }
             # Cache writable ?
             if (!is_writable(DC_TPL_CACHE)) {
                 throw new Exception("Can't write in cache fodler");
             }
             # Set file path
-            $f_md5       = md5((string) dcCore::app()->blog?->id);
-            $cached_file = sprintf(
+            $f_md5 = md5((string) dcCore::app()->blog?->id);
+            $file  = sprintf(
                 '%s/%s/%s/%s/%s.txt',
                 DC_TPL_CACHE,
-                My::CACHE_DIR_NAME,
+                My::id(),
                 substr($f_md5, 0, 2),
                 substr($f_md5, 2, 2),
                 $f_md5
             );
-            # Real path
-            $cached_file = (string) Path::real($cached_file, false);
-            // make dir
-            if (!is_dir(dirname($cached_file))) {
-                Files::makeDir(dirname($cached_file), true);
-            }
-            //ake file
-            if (!file_exists($cached_file)) {
-                !$fp = @fopen($cached_file, 'w');
-                if ($fp === false) {
-                    throw new Exception("Can't create file");
-                }
-                fwrite($fp, '1', strlen('1'));
-                fclose($fp);
-            }
-            // open file
-            if (!($fp = @fopen($cached_file, 'r+'))) {
-                throw new Exception("Can't open file");
-            }
-            // lock file
-            if (!flock($fp, LOCK_EX | LOCK_NB)) {
-                //throw new Exception("Can't lock file");
+
+            $file = Lock::lock($file);
+            if (is_null($file) || empty($file)) {
                 return false;
             }
 
-            $this->lock = $fp;
+            self::$lock = $file;
 
             return true;
         } catch (Exception $e) {
-            // what ?
             throw $e;
         }
     }
 
     /**
-     * Unlock update.
+     * Unlock file of update process.
      */
     public function unlockUpdate(): void
     {
-        if ($this->lock) {
-            @fclose($this->lock);
-            $this->lock = null;
+        if (!is_null(self::$lock)) {
+            Lock::unlock(self::$lock);
+            self::$lock = null;
         }
     }
 
diff --git a/src/Lock.php b/src/Lock.php
new file mode 100644
index 0000000..6b4cdca
--- /dev/null
+++ b/src/Lock.php
@@ -0,0 +1,148 @@
+<?php
+/**
+ * @brief activityReport, a plugin for Dotclear 2
+ *
+ * @package Dotclear
+ * @subpackage Plugin
+ *
+ * @author Jean-Christian Denis and contributors
+ *
+ * @copyright Jean-Christian Denis
+ * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
+declare(strict_types=1);
+
+namespace Dotclear\Plugin\activityReport;
+
+use Dotclear\Helper\File\{
+    Files,
+    Path
+};
+
+class Lock
+{
+    /**
+     * Locked files resource stack.
+     *
+     * @var    array<string,resource>
+     */
+    protected static $lock_stack = [];
+
+    /**
+     * Locked files status stack.
+     *
+     * @var    array<string,bool>
+     */
+    protected static $lock_disposable = [];
+
+    /**
+     * Last lock attempt error
+     *
+     * @var    string
+     */
+    protected static $lock_error = '';
+
+    /**
+     * Lock file.
+     *
+     * @param   string  $file           The file path
+     * @param   bool    $disposable     File only use to lock
+     *
+     * @return null|string    Clean file path on success, empty string on error, null if already locked
+     */
+    public static function lock(string $file, bool $disposable = false): ?string
+    {
+        # Real path
+        $file = Path::real($file, false);
+        if (false === $file) {
+            self::$lock_error = __("Can't get file path");
+
+            return '';
+        }
+
+        # not a dir
+        if (is_dir($file)) {
+            self::$lock_error = __("Can't lock a directory");
+
+            return '';
+        }
+
+        # already marked as locked
+        if (isset(self::$lock_stack[$file]) || $disposable && file_exists($file)) {
+            return null;
+        }
+
+        # Need flock function
+        if (!function_exists('flock')) {
+            self::$lock_error = __("Can't call php function named flock");
+
+            return '';
+        }
+
+        # Make dir
+        if (!is_dir(dirname($file))) {
+            Files::makeDir(dirname($file), true);
+        }
+
+        # Open new file
+        if (!file_exists($file)) {
+            $resource = @fopen($file, 'w');
+            if ($resource === false) {
+                self::$lock_error = __("Can't create file");
+
+                return '';
+            }
+            fwrite($resource, '1', strlen('1'));
+        //fclose($resource);
+        } else {
+            # Open existsing file
+            $resource = @fopen($file, 'r+');
+            if ($resource === false) {
+                self::$lock_error = __("Can't open file");
+
+                return '';
+            }
+        }
+
+        # Lock file
+        if (!flock($resource, LOCK_EX | LOCK_NB)) {
+            self::$lock_error = __("Can't lock file");
+
+            return '';
+        }
+
+        self::$lock_stack[$file]      = $resource;
+        self::$lock_disposable[$file] = $disposable;
+
+        return $file;
+    }
+
+    /**
+     * Unlock file.
+     *
+     * @param   string  $file           The file to unlock
+     */
+    public static function unlock(string $file): void
+    {
+        if (isset(self::$lock_stack[$file])) {
+            fclose(self::$lock_stack[$file]);
+            if (!empty(self::$lock_disposable[$file]) && file_exists($file)) {
+                @unlink($file);
+            }
+            unset(
+                self::$lock_stack[$file],
+                self::$lock_disposable[$file]
+            );
+        }
+    }
+
+    /**
+     * Get last error from lock method.
+     *
+     * @return  string  The last lock error
+     */
+    public static function getlastLockError(): string
+    {
+        return self::$lock_error;
+    }
+}
diff --git a/src/My.php b/src/My.php
index 32eca3d..6536825 100644
--- a/src/My.php
+++ b/src/My.php
@@ -24,9 +24,6 @@ class My
     /** @var    string  Activity database table name */
     public const ACTIVITY_TABLE_NAME = 'activity';
 
-    /** @var    string  Cache sub directory name */
-    public const CACHE_DIR_NAME = 'activityreport';
-
     /** @var    int     Incremental version by breaking changes */
     public const COMPATIBILITY_VERSION = 3;