I’ve have it set for 20 versions saved automatically, 1 every 5 minutes.
Actually, all the files .bak are shuffled up a number each time it saves a new version, so v20 is the oldest and the plain .bak (no. 01 is un-numbered!) file is always the latest.
I think what happens if you open any CPR which has a later .bak file of the same name then Cubase will offer to open that one instead for you on the basis that you either forgot to save last time or it crashed.
[I wish they automatically went into a sub-folder because I like a nice tidy project dir!]
I also use the Incremental Backup shortcut key (Ctrl-Alt-S) to quickly save a new version before doing important things (like vari-audioing or tempo mapping, things which have a tendency to crash…). This creates a new version of the file with a number at the end, and also starts you off on a new set of auto-saved backup versions too.
Mike.