How long does it take to upgrade a virtual machine?

I have a 6 GB virtual machine made in 2008, so it was made with a very old version of Parallels Desktop. It contains Windows XP. It's currently sitting on an external drive that I have, and I tried using Parallels Desktop 9 to open it, and it told me it had to convert it before it could open it. So I'm converting it now.

How long is it supposed to take to convert it? So far, it's been running for about two hours now, and it's still in the "Preparing" stage. But in my Mac's Activity Monitor, it indicates that Parallels is using 100% CPU, so it seems to be working really hard at something. And the disk image itself seems to have its "date modified" changed every minute, so it seems to be modified still.

So, I'm just wondering how much longer I have to wait for it to be done.
Thanks in advance!

 

Okay, so I managed to kind of salvage things. After force quitting Parallels and then re-opening the disk image with it a few times, eventually I was able to reach the Windows XP desktop. It blue screened immediately afterward though. But this meant that I could use Parallels Mounter to mount the virtual image's files so I could grab what I needed.