How do you make a partition NOT available?
 

I use a partitioned external drive. One partition is for SD backups, the other, much larger is for general stuff, movies, etc. Yep, I managed to do a SD back-up to that partition and wiped out everything that was there. Yes, my fault for not paying closer attention to the dialog boxes. But is there a way to make my general partition NOT show in SuperDuper so I don't pull this again?

There isn't a way to do this, no. Sorry - but we use the drives VERY explicitly everywhere, so a bit of mindfulness should help moving forward...

Also, if you're not repeatedly using the same source and/or destination, disabling "Convenience: Remember source and destination volumes" in Preferences can increase mindfulness a bit by forcing a conscious choice when manually running backups.

Maybe found a solution: eject the General partition.
 

Thank you for your replies. I have been fiddling around with this since I posted my question and may have found a solution. I ejected the General partition. It disappears from the Finder... and SuperDuper, leaving only the SD backup partition showing.
Again, my data loss was not this very good program's fault in any way. You do a good job or reminding users of what's about to happen. But since my General drive contains so much important stuff, this gives me an extra measure of safety. Again, thanks for your quick responses.

Another option is to use saved settings (File > Save), and open SD! by double-clicking the settings you want, which will include source, destination, options, etc...

Possibly the best option, though it's still wise to double-check that the source/destination volumes are correct because, at least in my experience, they haven't been 100% reliable… especially with temporarily mounted volumes (sometimes over a network).