Mr White describes exactly the same issue as I have. This is a serious question indeed.
As I explained, I am using the latest driver update. Backing destination is a local harddisk.
File backups are performed correctly, as well as Exchange Store backup.
The issue occurs when backing up individual mailboxes, all or selected, manual or with script.
The Retrospect window simply "vanishes" without a trace in the logs or backup history...
Maybe there is a command-line switch to run Retrospect in debug mode with more error logging?
I also tried this on another customers office (brand new server with SBS 2008 R1 64 bit + Exchange 2007) and same Retrospect version.
Unfortunately, SAME PROBLEM!
We have successfully sold version 7.6 to multiple customers running SBS 2003 and Exchange 2003.
However, brick-level mailbox backup is a requirement that our customers ask for (and it was one good reason why we started selling the product a few years ago).
So we can't sell Retrospect to our SBS 2008 customers until this issue is resolved...