I was backing up using Time Machine on my MBP (running Lion) to a shared drive on a mac pro 1.1 (Running Snow Leopard) via 1GB Ethernet, quite happily. After upgrading to Mountain Lion (EDIT: on the MBP, that is!) - no go. It gets part-way into the backup and then grinds to a halt. I moved the old sparsebundle somewhere else on the server and started a new backup - it created the new bundle OK and started copying. I left it overnight, but by the morning it had ground to a halt again. I'm expecting a long wait first time, but by "ground to a halt" I mean that the progress monitor hadn't moved for at least an hour and, when I looked in Activity Monitor, there was no significant disk, CPU or network activity happening. Clicking "Stop backing up" takes forever (until you see a time-out message in the system log), the bundle is still mounted (and won't eject - that locks up Finder) and restarting sits on a grey screen for several minutes before shutting down. Anybody else getting this, or is it just nature's way of telling me to switch to SuperDuper (which has just backed up my HD to a sparsebundle on the same server in a couple of hours with no drama)?