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Disabling the Guest Additions Time Synchronization

Posted: 22. Aug 2020, 18:32
by komm3
Trying to disconnect the time sync between windows 8.1 host and Linux guest.

Referencing the guide - 9.11.4. Disabling the Guest Additions Time Synchronization;
Once installed and started, the Oracle VM VirtualBox Guest Additions will try to synchronize the guest time with the host time. This can be prevented by forbidding the guest service from reading the host clock:

$ VBoxManage setextradata VM-name "VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled" 1

I modify the .vbox file in a text editor as described here;
https://superuser.com/questions/984040/ ... virtualbox

I use the following command;
<ExtraDataItem name="VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled" value="1"/>

I modify in text editor and save. The .vobx file is still associated with VB Manager app.

Once I save if I reopen the .vbox file my changes are there. Once I launch VB Manager and launch the VM however I change the time and it does not save within a minute it re-syncs to host o/s. I recheck the .vbox file and I see my changes are no longer there.

It appears that sometime during the boot process of the VM the .vbox file is changed back to original and my changes a above are removed.

For reference I copied the .vbox file saved to another directory and changed to .old so I have the original before changes.

Any idea why my changes are not saving properly?

Thanks

Re: Disabling the Guest Additions Time Synchronization

Posted: 22. Aug 2020, 19:00
by scottgus1
komm3 wrote:I modify the .vbox file in a text editor....I recheck the .vbox file and I see my changes are no longer there.
Did you notice the big warning at the top of the .vbox file?
<!--
** DO NOT EDIT THIS FILE.
** If you make changes to this file while any VirtualBox related application
** is running, your changes will be overwritten later, without taking effect.
** Use VBoxManage or the VirtualBox Manager GUI to make changes.
-->
Running the vboxmanage command makes the edit without the above side effect.

Re: Disabling the Guest Additions Time Synchronization

Posted: 22. Aug 2020, 21:04
by komm3
scottgus1 wrote:Did you notice the big warning at the top of the .vbox file?

Yes and ignored it

scottgus1 wrote:
<!--
** DO NOT EDIT THIS FILE.
** If you make changes to this file while any VirtualBox related application
** is running, your changes will be overwritten later, without taking effect.
** Use VBoxManage or the VirtualBox Manager GUI to make changes.
-->
Running the vboxmanage command makes the edit without the above side effect.
If only there was a forum or something that offered guidance on how to do that. Completely rhetorical of course.

Re: Disabling the Guest Additions Time Synchronization

Posted: 22. Aug 2020, 21:32
by scottgus1
komm3 wrote:If only there was a forum or something
Hey, what a cool idea! Maybe you and I could start one! :lol: