Cannot delete volumes of pre installed windows 8

I had exactly the same problem on a Sony Vaio with Windows 8 64 bit preinstalled, GPT partitioned. Used the bootable media with Acronis Disk Director 11 Update 2 and had the same error when trying to delete those partitions, telling me that the volumes are in use. Even the option of GPT to MBR failed and told me that the volume is in use. Eventually, I succeeded using the Windows 7 Ultimate 64 bit disk and deleting and formating the drive -640 GB one- at the disk options screen.
So,what seems to be the problem, as I see that there is still no answer at an identical situation?- and yes, I tried that with Legacy mode enabled and Secure boot disabled (and with them on, just to test)-

Remember that a GPT partition is created under Administrative rights, DD11 does not assume Administrative rights it just sees a partition and two main files on the Disk if it is Windows. Ususally these are Hyberfile.sys and Pagefile.sys, which recognises to DD11 that it is an Operating system. This is the same reaction that even in Windows under certain circumstances even Disk Management will not work correctly. For instance you may have two Operating systems and one Appears as D in your letter sequence and you wish to change the pathway so that either of you boot OS's can access the data drive as Drive D. You will find that Disk Admin will not change the path unless the Drive is powered Down or Disconnected at least once and booted into the previous OS before reconnecting and re powering and then rebooting into the system once again to achieve your goal.
Sometimes it is preferrable to partition and format a Drive before installation of a new OS. In say Windows 8 you wish to have 2 C Drives and make use of one Data drive. Doing this is easily achieved via the Disk Management interface, BUT you you must not give your new drive a letter before installation of the new OS like Windows 8. You can setup your TRIM and align your drive before you actually install Windows 8. On install of Windows 8 just tell it where to put your upgrade on custom install. Windows 8 will align itself as Drive C in its Root setup. The trick afterwards is to make sure your othe boot partition is not in the path of your Data drive or drives. Because you have not given the Drive a letter your new system resides on the OS has assumes it to be C, your other boot OS will appear at the back end of the lettering in Disk management. Because DD11 does not use the Windows OS it will not be able to make use of the fsutil the same way you can on GPT. It tries to be OS independant.
It doesn't matter if you use GPT or MBR partitions in any instance above you can achieve the same goal. If you have multiple OS's on your system like myself Windows 8 presents you with a boot menu GUI rather than Windows old setup of "Older version of Windows", which has been the best touch to it yet. Until we get a decent filesystem from Microsoft we can only minumize the problem of working with a combination of MBR and GPT extensions to how files and disk systems are handled.
Sorry for the long windedness of this comment but I fealt that you needed to understand some simple ways to get around some aspects of Windows that can be annoying.

Be aware Disk Director 11 is still being actively promoted and sold by Acronis with no mention of the fact that it does not support Windows 8. The only way to know is to dig into the Acronis support page. I'm sure many folks have paid for this product only to learn it hasn't been updated to work with Windows 8 and Acronis has admitted it had no plans to do so. This is a deliberately deceptive and devious practice by Acronis. Very disappointing. Otherwise, I enjoy using Acronis products. I wasted my money on Disk Director 11. I was duped.

Unfortunately, it's only after you purchase DD11, it says, in black and white the following:

"Supports Microsoft Windows 7, Windows Vista, and Windows XP. Windows 8 and systems with UEFI are not supported."

It even says that in the email you get. At that point in time, you should request your refund.

Also, on their requirements page, http://www.acronis.com/homecomputing/products/diskdirector/#requirements, it doesn't list anything about Windows 8.