Consider the following scenario. You try to install the original release version of Microsoft SQL Server 2005 on a volume mount point. In this scenario, the installation may fail because of insufficient disk space. Additionally, you receive the following error message:
There is not enough space on the destination disk for the current SQL Server installation. To proceed, free up disk space to make room for the selected features, select fewer features for this installation, or install the selected features to a different drive.
This problem occurs even if the mounted drive has sufficient disk space.
This problem occurs when the root path of the disk is mounted on a drive that has insufficient disk space.
For example, drive C has only 100 MB free disk space. You mount another volume onto drive C by creating a folder that is named data. The new volume has 3 GB free disk space. The new volume mount point is C:\data. When you try to install SQL Server 2005 on C:\data, the installation fails, and you may receive the error message.
This problem occurs because the installer does not recognize that the installation path points to a volume that has sufficient disk space. The installer incorrectly assumes that all paths below the root of a drive are on the same volume. This assumption is not valid for volume mount points.
To resolve this problem, make sure that the drive that is mounted to the root path has sufficient disk space to install SQL Server 2005.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.