When you install Enterprise Console 4.5 over an instance of MSDE SP4 named SOPHOS, the installer sticks at the 'Ready to Install' page.
The 'Install' button is greyed out and the user can not proceed. The available space and required space are both shown as 0 KB
Known to apply to the following Sophos product(s) and version(s)
Enterprise Console 4.5.0
The operating systems related to this article if any.
What To Do
Cancel the installation and try it again. It should now run correctly.