I have followed the instructions on how to create a minimal base image:
But my Mavericks.dmg created with Composer is 23GB. I even used monolingual to delete the language packs first. Where is this "hidden" data? When I look at the install - it only takes up 13GB of the drive (which is still huge!)
I have no idea how that could be happening, I captured a DMG with Composer that was <7GB in size (basically a fresh OS install with nothing added, I don't even think I booted it). Does Composer automatically ignore the sleepimage and swapfiles stored in /var/vm if you haven't already deleted them?
I use AutoDMG now, I highly recommend it.
Is that machine under management? Could it have cached down some of the installer packages or something like that?
I would also have to highly recommend using AutoDMG. It gives you a DMG that you can use within Casper just like Composer, but it has never been booted, so it doesn't contain any of the bloat.
Check out the following articles here on the Nation:
Remove as many items from the drive as you can that you are not going to use. And make sure to delete the contents of /var/vm