A question concerning the time synchronization between the host and the guest System.

I am using Windows 7 as my host OS and CentOS 7 is installed as VM in an Oracle VirtualBox environment without network access.

I am searching for a solution which allows the VM to get the correct time after a reboot or a snapshot. The challenge is, that I would collect the time from the host system without installation of additional tools. Do you have an idea?

1 Answer 1


If you guest is Centos Linux then you need to install DKMS (Dynamic Kernel Module Support) package.

# yum install dkms
# yum install virtualbox-guest-additions

For reference you can check this

Without virtualbox-guest-additions tool

Disable the ntp service

chkconfig ntpd off

For Windows Host

Go to
C:\Documents and Settings\.VirtualBox\Machines\
and edit the xml file.
–>Create a backup of this file<–

Add the line

VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled "0"

  • "Without installation of additional tools", do you mean that your yum install doesn't install anything?
    – Anthon
    Mar 14, 2016 at 10:39
  • hi, no yum is working no problem. i installed many thinks and all is working. i only recognized that the time is not synchronizing when I am working without network. So the idea was to sync the guest VM(CentOS7 ) with the host (Win7). But at the moment I have no success. and this command is not working for me: # yum install virtualbox-guest-additions
    – Mchoeti
    Mar 14, 2016 at 11:45
  • Check the recent edit. hope it works for you.
    – AReddy
    Mar 14, 2016 at 11:47
  • unforutnately not.. hm..
    – Mchoeti
    Mar 14, 2016 at 12:14
  • Does that line exist on that location.
    – AReddy
    Mar 14, 2016 at 12:21

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