We have newly configured Exchange cluster on Windows server 2003. The installation sequence was like bellow: * Windows member server 2003 * Exchange server 2003 * Exchange service pack 1 * Configure Windows cluster * Configure Exchange cluster * Install Antigen * Install Windows Service Pack 1 * Install Hot fix that solve OWA from Exchange cluster We shifted some mailboxes to this cluster from our old server for test purpose. Found the mails are not sent or received instantly, sometime it takes hours. Now Cluster is unavailable and it shows an error: Cluster service can not be started network path was not found error: 2147024843 (80070035) Exchange MTA service cannot be started. We thought it might be a problem related to antigen. For this reason we stopped the cluster services and disable the antigen but no result. Then we tried to uninstall it and stop all the services that are required except the Antigen Client and Antigen Central manager. In fact we didn't get any services like these. Now it has turned to very complex situation. Now we are not sure what could be the problem and how it could be solved. Osman Mahmud Banglalink