Unified Agent (UA) version 4.7.6 or newer does not run on an unpatched Windows 7 workstation. A fully patched Windows 7 workstations don't have a problem
Unable to connect to intercept because: The system cannot find the file specified
Previous versions of UA used SHA-1 code signing certificates. SHA-1 certificates were deprecated on January 1, 2017, so new versions of UA are signed with SHA-2 certificates. UA version 4.7.6 and later uses SHA-2 signed certificates. With a fresh install of Windows 7, without any Microsoft patches, does not support SHA2. When you install UA on a system that doesn't support SHA-2, the driver does not load.
*Please note: Windows 7 will no longer be supported for Unified Agent after end of life from Microsoft January 14, 2020. Windows 7 is not supported with WSS Agent.
Web Security Service
Install the patch that is associated with Microsoft Security Advisory 3033929. This Microsoft patch installs SHA-2 code signing support for Windows 7.
Symantec recommends a fully patched version of Windows 7 to work with UA.
However, as of this writing (25 October 2017), here is the minimal install for UA v188.8.131.52405 to work:
These requirements may change without notice with newer versions of Unified Agent.