[albee1952]

Once you open the older sessions, choose File>Save Session Copy> and make certain you check the box for "copy all audio files". Once you have saved your new versions, un-mount the old drive and try running the new versions. If they all open and play fine, then you are safe to reformat the old drive. If the old sessions don't want to open in PT8, it could be a plugin issue. In that case, try holding the Shift key while opening an old session. This will disable all the plugins.