I just finished going through the time sync problem, and here's the info I used: To configure ESX 2.5.x Server: http://tinyurl.com/ycpcfv To configure Windows Guest OS: http://tinyurl.com/yctxrr To configure CentOS w/o X installed, you still need to install the vmware tools. Edit the vmx file for your guest, tools.syncTime="TRUE". In grub.conf, add clock=pmtmr as a kernel option. You'll need to shutdown the guest OS, reload the vmx file, then restart the system. If you have X running, then you can use the vmware tools much like windows to configure time sync with the host system. HTH Mark