Also having mount problems
 

I have SD scheduled to create a bootable backup every night. I often wake to see that it could not find the destination volume, which is connected via firewire. The schedule window is left open with a spinning status circle. I am only able to quite the app with force-quit.

The one thing I can think that may be confusing SD is that I have two drives labelled "Bootable Backup" that I rotate between. I think the failures started after the first drive swap. Only one is connected at a time though. SD has no trouble seeing the destination drive in its dropdown when I first start the app and I am able to manually launch a backup. It is just the scheduled overnight backups that fail.

Dave will have to provide the answer, but I have a guess. SD keeps track of volumes not by their names, but by their unique ID numbers as assigned/used by the OS. Despite your two volumes being named the same, I am wondering if the script which is failing has not gotten associated with only the one of them. This would explain why the manual b/u works fine and the scheduled does not. As I say, this is a guess.

If you know (and you may not) does the script fail with BOTH externals or only with one of them?

We don't track drives by their name, but rather by their low-level identifier: as such, we won't be able to find the drive if you swap them. Drop me a note to support and I can provide you with a way to make this work...