Guest keeps reverting to most recent snapshot

[pinne65]

Vbox 5.010 win7 host, win7 guest based on immutable dynamic image

Whenever i restart or shut down and later start the guest from within itself it reverts to the most recent snapshot.

Shutting down by sending the "shutdown signal" from file/close doesn't do anything. That option has the restore checkbox disabled unchecked, "whereas the power off" has it enabled but still unchecked. Which makes me think that restarting or shutting down and starting from the guest shouldn't trigger a snapshot restore. But it does.

Is that the expected behaviour / default or is it a bug?

If it's not a bug, is there a way to change it?

TIA

[loukingjr]

from the user manual…

Immutable images. When an image is switched to "immutable" mode, a differencing image is created as well. As with snapshots, the parent image then becomes read-only, and the differencing image receives all the write operations. Every time the virtual machine is started, all the immutable images which are attached to it have their respective differencing image thrown away, effectively resetting the virtual machine's virtual disk with every restart.

[pinne65]

DOOH - it pays to read the manual.

I guess the option is on to teach people to read the manual

[pinne65]

So the manual says I can turn the autoreset feature off: vboxmanage modifyhd SOMEVDIMAGE.vdi --autoreset off.

To me, the manual makes it sound that I should apply this command the immutable image. However, I'm getting an error when I try to do that:
D:\Users\RTFM\VirtualBox VMs\Win764IMMUTABLE>vboxmanage modifyhd Win764IMMUTABLE.vdi --autoreset off
VBoxManage.exe: error: Medium 'D:\Users\RTFM\VirtualBox VMs\Win764IMMUTABLE\Win764IMMUTABLE.vdi' is not differencing
VBoxManage.exe: error: Details: code VBOX_E_NOT_SUPPORTED (0x80bb0009), component MediumWrap, interface IMedium, callee
IUnknown
VBoxManage.exe: error: Context: "COMSETTER(AutoReset)(AutoReset)" at line 661 of file VBoxManageDisk.cpp

The message makes me think I need to apply the command to the most recent snap shot file and that I should have run the command against the now immutable disk image after I had my base OS with updates installed but before I made it immuatble.

I'm about to try it out but waiting for a backup to finish first...

[pinne65]

Ok - seems that did the trick

Just a WARNING- just because you set autoreset to off on your most recent snapshot, that property setting is NOT inherited by subsequent snapshot.

I find this a tad annoying to say the least. It makes more sense for this feature to be off by default or at least the setting to be persisted down the chain of snapshots.

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Disclaimer: I might have missed something in the manual again - If I read the it, the probability is 50/50 or better.