Single Instance

This option is associated with the Archiving Options (File System/Exchange Mail)

See http://www.symantec.com/docs/HOWTO74057 - Default Settings for the Archiving Option

Having the Exchange Mail Archiving Option or File System Archiving Option selected from the Install Options would activate the 'Archive' option in Backup Exec Settings.

In the install options I cannot find this option. Perhaps PKH is right and is this not an option in BE2012 SBE. I need this option so I don't backup duplicate files. It is strange that the help function in BE2012 SBE mention this item while it is not supported in BE2012 SBE

You say: so I don't backup duplicate files.
Do you mean the Backup Exec Deduplication option ?

Not sure if that is an available option for the BE 2012 SBE edition.

That is correct. BE2012 SBE should backup just one file and mark the duplicate file. We are told that this function standard is disabled and can be enabled in the settings of BE2012 but I can't find this option.

That is correct. BE2012 SBE should backup just one file and mark the duplicate file. We are told that this function standard is disabled and can be enabled in the settings of BE2012 but I can't find this option.

That is a separate option you must purchase, but I am not sure if that is available for the SBE edition.

As the name suggests, the SBE edition is meant for small businesses with few requirements.  If you need the dedup option, upgrade to a full version of BE and purchase the dedup option.  You would not have to re-install BE.  All these are just change in licences.

Do note that the dedup option has pretty high requirements, like a 64-bit machine for the media server and lots of memory.