virtualbox.org

Im using Win 7 pro on my macbook and Im trying to figure out how to reduce the size without 3rd party weirdness like that XP emulator or anything.
So what can I do? All I really need Windows for is a few small programs and for easy communication with my Home server.
I need to be able to use remote desktop, a few small programs for external device support.
Basically just stuff for my RC helicopters and Networking with other Windows users. My problem is that my mac only has 250GB storage. Its a new Pro so Im able to give my VM's plenty of power, just not a lot of storage. When I first installed Windows in VBox, it was like 13GB. Then of course it started updating and doing all its stupid, uncontrollable windows crap and now Its at 22Gigs!! Also thats without a snapshot. I figured out how to save backups to an External hard drive without cloning but still have yet to use it. Time machine backs up everything anyways so I'd assume it backs up my VM states as well. Ive got tons of external storage so thats not a problem. I would try and just attach the VDI from external drive but I terrified about losing my activation. Microsoft licenses are one of the worse things ever and I never want to have to deal with it again. Its a long story but the short of it is if Windows manages to lose ALL of you files one day as Windows simotaneously shits the bed, the wonderful people at Microsoft will offer to sell you windows 8 for 150.00 with an option for office 2013 for only a few hundred more and thats really all they can do for you sir.
Anyways, back on track, I hate Windows but unfortunately I find myself needing it. But I cannot justify giving it a 25gig plot staked out on my disc. So if anyone has helpful advice on how to compress certain system files or erase entire chunks, I'd love to hear them. Someone needs to figure out how to compress everything and only unpack as needed very quickly. That would be rad!!
I dream of a day when all OS's are virtual and disposable and all we worry about is our personal files.

You can move a VM to a different drive without affecting Activation as long as it's running on the same host.
See Moving A VM

I'd suspect, that would be a good Google search project. Virtualbox would probably not be able to help. Same thing as if you wanted to shrink the Windows install on a real hard drive.

You could put the guest folder with the .vbox file, the logs, and the virtual drive file on an external USB3 or e-sata drive, and as long as your host keeps the same designation for that external drive you could run it from there. E-sata should be as fast as an internal connection to the drive, USB3 may be as well, I haven't played with it enough. USB2 will possibly cause the guest speed to suffer from limited drive-data bandwidth. And of course you don't want to unplug the drive while the guest is running.

Activation will likely not cause you problems, since the "guts" of the guest is going to stay the same. In fact, copying the guest folder and files to another drive is a great way to do a full backup - just copy it back and re-register the guest with Virtualbox.

Alternatively, as of 11-21-2014, a new 1TB spinning-platter laptop drive is $69 on Newegg...

Yea, I made a copy of the VDI before removing snapshots and got a clone to yesterdays state. The preview document has the same values so Im sure that if I remove the current machine and import the one on external, it should work. Later Ill just try and do a copy of a current, no snapshot VDI and a clone of its state and then the clone will be barely anything at first and I can just have the external VDI attached. Then I can have full blown Windows with 300Gigs or something. I just think it would real nice if Microsoft made a portable Windows OS. I have 3 different Linux distros not including vagrant and I can do whatever I want with em. Someday people will learn how to put source code for there drivers and software in a repository so people can compile it for whatever they want. Then I can say peace out Windows!! I have and use MATLAB and for there license, its attached to your account and is verified online whenever it needs to and thats it. And on MATLAB you pay for a bunch of hardware support but you only download them as needed and can toss it, keep it, whatever. But a VBox app made just for external disk and lightweight versions of those OS's with option to install product as you go would just be to awesome for Microsoft to do.