• hi, you may look on the client machine for the sep_inst.log under %temp% folder.
• search for the value "return value 3"  just above/below  the line there should the error why it failed.

Cheers
Pete!

There should be an .err error file or .log file in the directory that was just created for SEP.

SEnd the Installation log file.

Meanwhile u may go htorugh the link  Documents.
http://service1.symantec.com/support/ent-security.nsf/854fa02b4f5013678825731a007d06af/ae142cf6efe920cf88257376005f1474?OpenDocument

Usually if this is the error "No error message, just say, the wizard was interrupted"

There is a pending restart or task for the microsoft installer, setup cannot continue until these are finished.

Before you run the setup again, please check for "msiexec" process running, then try to kill the process..

Checking your log;

Error Code: 1708 means "Installation operation failed."

Error Code: 1603 means "A fatal error occurred during installation" which can lead to several cases this problem evolves around SYSTEM account permissions on the target system, free disk space on the target system, or bad file download or locked/inaccessable file.

So based from the log, usually this is at the end. Please post more log entries before this events.

Any reason why you need to install via GPO ? You should be able to do it via a computer startup script, which runs the setup.exe on startup of the pc.

We have modified the old SAV 10.1.5 logon script for this use and have tested it fine. SEP client installs fine and with no errors.

Regards,

Jon.

In the SEP-INST look for the first return value 3 and post 10 lines above it.

Since you are using vista you should first consider this document and make sure UAC is turned off before GPO or any deployment.

Symantec Endpoint Protection: Preparing computers that run Windows Vista for remote client deployment
http://service1.symantec.com/SUPPORT/ent-security....

Im Having a similar problem.
We are gradually upgrading all workstations to SEP from corporate edition 10.x  (+/- 4500 workstations) at this point I have about 1000 SEP clients and working very well.
but sometimes the installation (pushed via sepm) just fails in the same way as explained above and the client stays working with version 10.x
In the sep_inst.log i dont have any "return value 3"
I do have a lot of:-
info 1603 where dll`s are being held in use by a certain process for example ccsetmgr and at the end

MSI (s) (28:74) [15:12:04:673]: Note: 1: 1708
MSI (s) (28:74) [15:12:04:673]: Product: Symantec Endpoint Protection -- Installation operation failed.

i can post the whole log if needed

Thanks

Gary

Try runnig cleanwipe and re-run the install. 

can i run cleanwipe remotely?

Well you can access the Scheduled jobs of that client by \\client name
Add this cleanwipe as scheduled task..it will automatically run after 30 seconds.
There are few more commands that can used for that read the readme.txt that come along with cleanwipe.zip