How to create differencing disk?

[Daimroc]

I am using the last version of virtual box, v4.2.10, and when I try to create a differencing virtual machine I don't be able to work.

I am followinf this steps:

1.- Create a new virtual machine, in this VM I create a new disk.
2.- Install the OS, Windows XP and update it. Install other base programs.
3.- With vboxmanage I change to immutable this base virtual disk.
4.- I create a new virtual machine, I select the immutable disk. this create a new snapshot.

However, in the configuration, in the storage section, I see that the disk that is used is my base disk, not the {xxxx} disk.

I ensure that the {xxx} disk is normal and autoreset off, to ensure that the changes are saved. But When I restart my second virtual machine always have the initial state of the base disk.

Am I doing something wrong?



Thanks.
Daimroc.

[mpack]

1. Create A, the original VM.
2. Create B, a linked clone of A.

A and B will both then be based on differential disks.

I hope you did your reading and understand how unreliable (and disk space hungry) differential disks can be.