Users have asked why space is required on the system drive (typically the C: drive) when they choose to install Visual Studio 11 to another drive.

While Visual Studio 11 does allow you to install the majority of features to another drive, VS11 still requires space on the system drive for the following reasons:

• Shared runtimes like the .NET Framework and Visual C/C++ which require installing into the system drive.
• Packages shared with other products that have their own installation folders like SQL Server and Windows SDK
• Components shared with other applications like Office or services like IIS
• Windows Installer and package caches

For Visual Studio 11 Ultimate Beta, about 45% of the entire installation is located on the other drive. We are working to improve that experience but significant drive space will still be required on the system drive for those reasons above.

If you have significant disk space available, I recommend you do not create “system partitions”. The system drive is often used for temporary system files, caches of various sorts, and is the default location of %ProgramFiles% unless modified at initial install time using unattend files.

You might instead consider having a partition for the system and applications, and a separate partition for data (documents, source code, builds, etc.). This makes rebuilding a machine easier since, at most, you’d only need to reformat and reinstall one partition (for a domain-joined machine).

If your disk is not large enough or you already have a smaller system partition, there are some other techniques you can explore like mounting another volume as an empty folder, though this may not be supported for folders under %SystemRoot%, %ProgramFiles%, or even certain folders under %ProgramFiles%.