If the Oxford Sophos Antivirus Installer fails to install Sophos for Windows it will display a red shield and the message Install Failed. There can be a number of reasons why the installation fails but the most common reason is that you already have another antivirus software product installed such as a product from Norton, Mc Afee, AVG and others.
If you already have up to date antivirus software installed and protecting your computer then you don't need to install Sophos as well.
On Windows and OS X systems the shield may occasionally disappear for a short time while Sophos is installing updates.
Normally however it will reappear within a few minutes.
[11/Nov/2015 ] (PID: 20476) Sophos_plugin: Downloading /opt/kerio/mailserver/sophos/new ...in the Windows system tray (usually bottom-right of the screen, near the clock) then Sophos is running properly. To view the shield on Windows 7 see the answer to the question Why can't I see the Sophos shield in the Windows system tray or OS X system status bar (near the clock)? Sophos for Mac OS X On OS X the shield appears in the system status bar (usually top-right of the screen) and is black rather than blue. The Sophos client updates automatically via the Internet - you don't have to update it yourself.Depending on the version of Sophos the shield may be solid (version 7) or appear as an outline (version 8). The current Sophos client will continue to update automatically until November 2012 at which point you will have to download and install a new version of the software.If you want to switch to using Sophos instead you should first uninstall the other product using the menu.If you have uninstalled any other antivirus software and still have problems installing Sophos then you will need to send us some log files to help us figure out what has gone wrong.[11/Nov/2015 ] (PID: 20476) Sophos_plugin: Maximum thousands loops around central pattern-matching loop: 500 [11/Nov/2015 ] (PID: 20476) Sophos_plugin: Maximum count of files in parent archive: 10000 [11/Nov/2015 ] (PID: 20476) Sophos_plugin: Maximum length of decompressed data from the current compressed stream: 256 MB [11/Nov/2015 ] (PID: 20476) Sophos_plugin: Ignore encrypted files: 1 [11/Nov/2015 ] (PID: 20476) Sophos_plugin: The plugin is prepared for updating phase [11/Nov/2015 ] progress event: S [11/Nov/2015 ] (PID: 20476) Sophos_plugin: Checking for Sophos antivirus update on sophos-update...