Hi, After using the free edition of v5.1 for a while I decided to go for the free edition of V6. Uninstallation of previous version as well as installation seemed to work fine on my Windows XP sp2 PC. The system where up and running until first reboot of the PC. Following from the server log after reboot: 23:31:07.515 CallCtrl::thread [CM501008]: *** Stopped Calls Controller thread *** 23:31:07.500 CServiceModule:reMessageLoop [CM100001]: *!* Failed to initialize Call Manager *!* 23:31:07.500 CallMgr::Initialize [CM100001]: *!* Failed to initialize SIP Stack *!* 23:31:07.500 CallMgr::Stack::Initialize [CM101002]: Can not create UDP transport on 192.168.1.39:5060 23:31:07.500 ResipLogger:Failed to create transport: V4 UDP 5060 on 192.168.1.39[br] 23:31:07.500 ResipLogger:[ V4 192.168.1.39:5060 UDP target domain=unspecified mFlowKey=564 ] already in use [br] 23:31:07.500 CallMgr::findLocalIPs [CM501006]: Default Local IP address: [192.168.1.39] 23:31:07.359 CallCtrl::thread [CM501007]: *** Started Calls Controller thread *** 23:31:07.343 CallMgr::Initialize [CM501002]: Version: 6.0.606.0/Beta 23:31:07.343 CallMgr::Initialize [CM501001]: Start 3CX PhoneSystem Call Manager 23:31:07.343 LoadLicenceInfo [CM501010]: License Info: Load Failed Anyone with any idea of what might be the problem?