Index: /trunk/roundcubemail/program/include/rcube_cache.php
===================================================================
--- /trunk/roundcubemail/program/include/rcube_cache.php	(revision 4783)
+++ /trunk/roundcubemail/program/include/rcube_cache.php	(revision 4784)
@@ -209,5 +209,5 @@
 
         if ($this->type == 'memcache') {
-            $data = $this->db->get($key);
+            $data = $this->db->get($this->mc_key($key));
 	        
             if ($data) {
@@ -264,4 +264,5 @@
 
         if ($this->type == 'memcache') {
+            $key = $this->mc_key($key);
             $result = $this->db->replace($key, $data, MEMCACHE_COMPRESSED);
             if (!$result)
@@ -314,5 +315,5 @@
 
         if ($this->type == 'memcache') {
-            return $this->db->delete($key);
+            return $this->db->delete($this->mc_key($key));
         }
 
@@ -326,3 +327,14 @@
     }
 
+
+    /**
+     * Creates per-user Memcache key
+     *
+     * @param string $key Cache key
+     * @access private
+     */
+    private function mc_key($key)
+    {
+        return sprintf('[%d]%s', $this->userid, $key);
+    }
 }