Our company recently upgraded to new computer and software. After installing CS6 Photoshop I was trying to edit a rgb format file, but there was no option for SGI rgb. For earlier versions of Photoshop we were told to download 3 party plug-in to get this format to work. Our IT person said that the 3 party plug-in can no longer be used with CS6. I have a majority of my files as rgb and would like to edit these files, how can I do this? Is there a option during CS6 install for getting this format?
Nope. Use an external converter like XnView or IrfanView.
There's no need for third party software - just install the optional file format plugins.
Photoshop has had SGI RGB format support for many, many years.