back up files

how do i change a back up file for a cubase project into a usa-able cubase file…i know i have to change the file name ‘bac’ to something else (csh?) but how do i do that and what is the extention i should use ???

Change .bak into .cpr by clicking the file and then F2.

Or easier still, you can go to open your project, but in the dialog instead of Files of type: Cubase Project File(.cpr), select ‘Any Type’

…then you’ll be able to see and load backup files without changing the filename. Once loaded, simply save to a new name