Why the installation terminates with error about Graphical User Interface DLL?
This applies to F-Secure Anti-Virus for Microsoft Exchange 6.40 and earlier on any of the supported platforms. When installing the product on an Exchange server, the installation fails right in the beginning with an error message “Unable to initialize Graphical User Interface DLL (Fssgui.dll)”. After clicking the OK button the installation terminates. This error occurs in situations where there has been a previous installation (or attempted installation) of some certain F-Secure products on the server and there are some registry settings left behind from that. To solve this problem the registry settings need to be removed. To do that, perform the following steps: • Start the Registry Editor by clicking Start -> Run… and type Regedit in the prompt. • Find this registry key: [HKEY_LOCAL_MACHINE\SOFTWARE\Data Fellows\F-Secure\Customization\]. • Delete it and all the branches under it. After doing this, please start the F-Secure Anti-Virus for Microsoft Exchange installation again.