You can download the client package of 12.1 RU3.
There is one known issue in 12.1 RU2 for Window 8 which fixed in 12.1 RU3.
After applying Microsoft update KB2781197 to a Windows 8 computer, the
Symantec Endpoint Protection client installer fails
Fix ID: 3123310
Symptom: The following lines are from the SEP_INST.log generated from a failed installation attempt:
(SERVER) MSI (s) (04:18) [08:56:49:093]: Executing op:
CustomActionSchedule(Action=ShowServiceProgress,ActionType=3073,Source=BinaryDa
ta,Target=ShowServiceProgress,CustomActionData={3771A34D-2132-48EA-A486-
D62ECDF9D553};SOFTWARE\Symantec\Symantec Endpoint Protection;Executing install
script via service;)
(SERVER) MSI (s) (04:5C) [08:56:49:250]: Invoking remote custom action. DLL:
C:\WINDOWS\Installer\MSI6B0.tmp, Entrypoint: ShowServiceProgress
(UNKNOWN) ScriptGen: ShowServiceProgress() MSIRUNMODE_SCHEDULED
(UNKNOWN) ScriptGen: ShowServiceProgress() calling
WaitForSingleObject(scriptStarted) ...
(UNKNOWN) ScriptGen: ShowServiceProgress() WaitForSingleObject(scriptStarted)
returned WAIT_OBJECT_0
(UNKNOWN) ScriptGen: ShowServiceProgress() script execution failed.
(UNKNOWN) ScriptGen: ShowServiceProgress() reset script failure event.
(UNKNOWN) ScriptGen: ShowServiceProgress() is returning an error (so close to
the end!)
(UNKNOWN) CustomAction ShowServiceProgress returned actual error code 1603
(note this may not be 100% accurate if translation happened inside sandbox)
Solution: For installations on Windows 8, removed the option to enable/disable Windows Defender after
install, as this is no longer supported. Windows Security Center (WSC) will automatically disable Windows
Defender when Symantec Endpoint Protection registers with WSC.