When using DPM 2007 to backup an Exchange 2007 server, you may encounter this:
“DPM encountered a retryable VSS error ID 30112. Details: Unknown Error 0x800423f3“
I have read where this was an issue with Exchange 2007 if the rollup pack is 3 or less. The article looks like it was updated on February 19th, so the problem likely still exists.
Here’s the link to the “fix”.
Basically, you have to restart the Information Store and Exchange Replication services to workaround it.