So what do I do if I have a 30GB VPC and 11GB of free disk space?
There are several methods you can use to decrease the size of your virtual hard disk (VHD) files. One of the lesser known methods is to decrease the Windows system file checker (SFC). To disable to SFC on your guest operating system you can simply open a command prompt from within it and type the following commands:
Doing this can typically decrease the size of a VHD file by nearly 300 MB. Saving this much spacer per virtual machine can add up very quickly.