May sound like a stupid question but can somebody explain the difference between backing up a case in FTK 1.8 and saving?
Backing up a case will copy all the files located in the case directory to a specific folder you specify. This is useful for when you want to quickly backup the case to external media without manually locating the case files and copying them yourself. Beware that this won't back up the image that you are analysing, that will need to be backed up yourself I believe. Make sure you reverify any files that you have copied.
Saving a case just does that - save. It will overwrite any previously saved data.
I tend to backup the case every 20 - 30 minutes, FTK 1 crashed on me once and I lost all the case data like saved bookmarks and the indexing database - luckily I was analysing my own USB device at the time!