Didier, I'm running a PersonalAlpha V1.1.2 in a multi-architecture cluster since a couple of years and have not seen this behaviour. But I'm using NTP, so this may make a difference. Can you use NTP ? Do you use the Stromasys IDLE tool (IDLE V1.2) ? Is your PersonalAlpha very busy ? High CPU or IO load ? High network laod ? Volker.