After the installation of PST Enterprise, you may see a warning message displayed on the final step of the installer:
"This machine must be restarted. Please restart this machine to complete the installation of PST Enterprise."
This occurs when the installation process needs to replace a Windows file that is in use. Depending on the file involved, some parts of PST Enterprise may be unaffected but it is recommended that you reboot the server at the next opportunity before using PST Enterprise.