id summary reporter owner description type status component version resolution keywords cc guest host 6250 Virtual clock synchronization giving up on new kernels Ondřej Buriánek "Hello, last references for lines like following i found for VirtualBox version 2.x.x, so i am reporting as new defect (unsuccesfully have been fighting with it for few weeks). {{{ 199591902:03:47.066 TM: u64DeltaPrev=-1326594272658 u64PrevNanoTS=0x0000016f3d7e0d13 u64NanoTS=0x0000003a5e4fdf81 199591902:03:47.066 TM: Not bothering to attempt catching up a 18 446 742 747 087 831 003 ns lag; new total: 18 446 744 073 654 626 217 }}} These lines filling Virtual Machine (Windows 7, Ubuntu) log file after powering, machine is so slow it won't boot. Source of this error is in http://www.virtualbox.org/svn/vbox/trunk/src/VBox/VMM/TM.cpp (tmR3TimerQueueRunVirtualSync). Enabling/disabling in VM VT-x has no effect, (VT-x is enabled in bios, cpu is cappable). I tried several kernels (ubuntu karmic) so result is following {{{ 2.6.30-5 - works excellent 2.6.31-17 - failing 2.6.32-13 - failing 2.6.32-02063208 - failing }}} I also used few versions of VirtualBox, all failing with new kernels Official 3.1.4, 3.0.12, Opensouce 3.1.2 " defect closed VMM VirtualBox 3.1.4 fixed TM time sync lag Windows Linux