Parallels 7 Configuration Options – Expanding the Initial HD Size
If you plan on using Window in Parallels for storage of files or to run a specific program you will need to change the initial installation default HD size of 64GB (32GB for earlier versions). You can expand the default partition before or after the installation, however in my experience, expanding the partition after Windows is installed has created many problems (i.e. Windows has blue-screened or has lost the boot-loader). Without the involvement of Parallels Tech Support, it has been be very difficult to repair this problem. Therefore expanding the HD before Windows is installed is my recommendation.
To expand the 64GB default partition during installation, carefully watch each screen during the installation for the following screen and press Configure before pressing Continue:
Press Hardware and select the Hard Disk 1 menu option and press Edit… to find the HD resizing option.
The default 64GB Size will be selected. Ether slide the adjustment arrow to your desired size or type in the size in Gigabytes. Leave the check boxes at there default and press Apply then Close.