I was able to get my VM to qualify. Make sure you have the required hotfixes, otherwise you will not qualify -- KB3035583 and KB2976978 for Win8.1, KB3035583 and KB2952664 for Win7 SP1.
Then reboot and run the batch file given here: http://superuser.com/a/922442
I do all of my work in a VM, and as my org gets new machines, I xcopy the VHD over with minimal downtime. Full screen remote desktop is fine. My work is generous with hardware dollars, so I'm not really in any need of more memory or disk space.
That said, my work doesn't really involve anything involving lots of screen drawing. Video sucks through remote desktop (audio/video de-sync or rdp connection drops), so if I need to watch a video (presentation or youtube), I either suffer through it or do that on the host machine.
In the present time though, I tried this once on my work laptop, running a Core i7(2011), with 8GB RAM and Windows 7 as the Host OS and VM OS. With the usual platter HDD, Visual Studio got bogged down so much during compilation times(we had a really big project), that it became too unfeasible to continue using.
For example right now, a rather major regression in ext4 conversions: The convert goes find, mount is fine, rollback is fine. But if you scrub it, hard panic; even console is lost, let alone all services. But the fs survives. If you balance it, corruption of the fs (and so far not repairable). So right now, which could change at any moment, I'd say avoid ext4 to btrfs conversions. Create a new fs, and keep backups. Usually it's pretty good about at least mounting read only so you can update a backup, even if the fs is beyond repair.
Despite piles of kernel features, it still lacks much needed notification to user space of device failures. For multiple device volumes, you probably want to be informed of either flakey or failed devices and right now you have to be watching for it. Some edge cases in degraded operation exists when replacing devices that you have to be careful of, etc. So this whole area needs work, which means more developers interested in such things are needed.
But anyway, it's going pretty good.
Last time I tried that meant having to do a rather slow and disk hungry export followed by an import. Was I doing it wrong and is there no way to just copy the disk and machine definition, or are there other ways already?
If I need to move a VM for some reason, I copy the entire VM directory to the new location then open VirtualBox and use "Machine" -> "Add ..." and select the directory with the VM config and files.
I hope that helps, unless I missed something.
Does this work or could the VMs get corrupted?
Host volume mapping is a folder shared between the host and the VM?
Yes.
Hosts:
Notebook runs Linux Mint 17 with VirtualBox 5.0
Desktop runs Windows 7 with VirtualBox 4.3 (5.0 ha an issue on Win7 that Oracle won't fix, but prevent my VM from starting)
Guest:
Xubuntu 15.04 with the VirtualBox 5.0 Guest Additions
It's a surprisingly performant day-to-day system, which I can snapshot to try out things, move to other machines if I need to, make backups etc. About the only thing it doesn't do well is really CPU intensive or GPU intensive operations.
But it works fine for 2 monitors, web browsing, watching videos, etc.
It's kind of surprising actually.
From time to time I'll also spin up some Linux VMs and do various dev activities in a real Linux, which I usually just background and ssh into from my Windows VM. It's kind of nice having a virtual rack of machines to monkey around on.
Less impressive has been trying to get Ubuntu to not feel terrible, but Centos works fine.
If I need better performance, I'll dive back to the host OS and do those things, but it's mostly just for gaming or music production.
Bonus, my host OS has stayed relatively free of junk and stays really snappy, even all this time later.
My only recent problem is that the Windows 10 updater won't qualify the VM guest for the upgrade. So I'll probably have to grab the ISO and try it that way.