diff --git a/lib/kolab_sync_data_email.php b/lib/kolab_sync_data_email.php
--- a/lib/kolab_sync_data_email.php
+++ b/lib/kolab_sync_data_email.php
@@ -50,6 +50,8 @@
         'to'                    => 'to',
     );
 
+    static $memory_accumulated = 0;
+
     /**
      * Special folder type/name map
      *
@@ -288,6 +290,7 @@
         else if ($airSyncBaseType == Syncroton_Command_Sync::BODY_TYPE_MIME) {
             // Check if we have enough memory to handle the message
             $messageBody = $this->message_mem_check($message, $headers->size);
+            static::$memory_accumulated += $headers->size;
 
             if (empty($messageBody)) {
                 $messageBody = $this->storage->get_raw_body($message->uid);
@@ -1661,6 +1664,14 @@
         }
     }
 
+
+    private function mem_check($need)
+    {
+        $mem_limit = parse_bytes(ini_get('memory_limit'));
+        $memory = static::$memory_accumulated;
+        return $mem_limit > 0 && $memory + $need > $mem_limit ? false : true;
+    }
+
     /**
      * Checks if the message can be processed, depending on its size and
      * memory_limit, otherwise throws an exception or returns fake body.
@@ -1675,7 +1686,7 @@
         //       as streams). It also happens when parsing the plain/html text body
         //       in getMessagePartBody() though the footprint there is probably lower.
 
-        if (!rcube_utils::mem_check($size * 5)) {
+        if (!$this->mem_check($size * 5)) {
             // If we already rised the memory we throw an exception, so the message
             // will be synchronized in the next run (then we might have enough memory)
             if ($memory_rised) {
@@ -1693,7 +1704,7 @@
 
                 if (ini_set('memory_limit', $memory_needed) !== false) {
                     // Memory has been rised, check again
-                    if (rcube_utils::mem_check($size * 5)) {
+                    if ($this->mem_check($size * 5)) {
                         return;
                     }
                 }