Download the Clonezilla live ISO image and mount it as a CDROM drive for your virtual machine
Once loaded, press enter on the first option(default). It will then ask for a language (defaults to English) and a keymap. If you are not sure, just press enter on the defaults. It will then ask to start clonezilla or to open a shell. Choose to open clonezilla:
Then choose the type of cloning you want to do. In this case, choose disk/partition to disk/partition:
and then choose disk to local disk. Choose your source disk(the old smaller size one) which will probably be /dev/hda and your target hard disk(the bigger one) which will probably be /dev/hdb.
Next, we have the parameters window. I’ve unchecked the first option which was to reinstall grub in the target disk, which we don’t want since we only have Windows. So it will look like this:
On the next screen, choose to use the same partition table as the source disk.
I will then warn you a couple of times that all data in your target partition will be lost. Since we are sure about this, we continue with the process.
This may take a long time depending on the size of the source disk, so you can download GParted’s ISO image in the meanwhile for the next step.
Once the process is finished, power off the machine using clonezilla’s menu options(or just power it off).
Now, remove the old hard drive from the VM and add the new one as master. Unmount clonezilla’s ISO. If you boot your VM now, Windows should boot normally, but if you check your disk size, it will tell you the same size as the old drive. WTH! Don’t panic.
Shut down your VM again and mount GParted’s ISO so it boots from it. Choose the auto-configuration option(the first one) and once it starts up it will show you a partition manager window. It will show your current partition plus some unallocated space to the right. Right click on the current partition an choose ‘resize/move’.
The new screen will let you drag the arrows to the desired size. So go ahead with it to the far right(if you want the entire disk space for windows) and click apply.
That’s it! once it is done, you can shutdown, unmount GParted and boot into your Windows VM with brand new hard drive space and everything working as it was before.
**Parallels users can first resize the virtual hard drive using the included “Parallels Image Tool”, but will need to use GParted to make Windows recognize that new size.
*** Credit to Marcos for the stellar steps for this process!