Hello,
Upon checking the Logs, we see the following Errrors:
ScriptGen: ShowServiceProgress() WaitForSingleObject(scriptStarted) returned WAIT_OBJECT_0
ScriptGen: ShowServiceProgress() script execution failed.
ScriptGen: ShowServiceProgress() reset script failure event.
ScriptGen: ShowServiceProgress() is returning an error (so close to the end!)
CustomAction ShowServiceProgress returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox)
MSI (s) (68:68) [15:29:56:772]: User policy value 'DisableRollback' is 0
MSI (s) (68:68) [15:29:56:772]: Machine policy value 'DisableRollback' is 0
Action ended 15:29:56: InstallFinalize. Return value 3.
To check the root cause, I would require the SIS_INST.log as well...
By that time, I would recommend you to -
1) Turn off the UAC from the client machine, restart the client machine
2) Install the unmanaged SEP client from the DVD of SEP 12.1 on the client machine.
Symantec_Endpoint_Protection_12.1.2_Part1_Installation_EN\SEP\setup.exe
Install only AV/AS feature only
and check if that is getting installed.
Secondly, check these Threads which refers to the same issue -
https://www-secure.symantec.com/connect/forums/sep-121-client-installation-failure
https://www-secure.symantec.com/connect/forums/wizard-was-interrupted-symantec-endpoint-protection-could-be-completely-installed-1
Hope that helps!!