Dropbox Incompatibility, Workaround
 

I've used SuperDuper! for years. Backing up to a firewire drive with smart update takes 15-45 minutes, and backing up over the network to a Drobo box, also with smart update, has taken 45-90 minutes.

I just upgraded to 2.7.3, and the network backup ran for 6 hours without finishing. I looked at my CPU usage (thanks, iStat!) and saw that Dropbox was the most active process. So I stopped the backup, disabled Dropbox syncing, and restarted the backup. It took 45 minutes. Same thing today: the two backups took just about the same length of time. I re-enabled Dropbox syncing, and it took a couple of seconds for Dropbox to conclude that everything was up to date.

So there's some bogus interaction between SuperDuper! and Dropbox, but it's easy to work around: just disable Dropbox syncing during the backup, and re-enable it when finished.

Dropbox is likely monitoring file system changes in an inefficient way. Your backup was doing a lot of copying, and that caused its daemon to go a bit crazy. They need to fix that...we're not interacting with them in any specific way, and we're not doing anything weird, undocumented, etc.

Agreed; I didn't mean to imply otherwise. That's why I didn't call this a SuperDuper! bug. <g>