> And I was wrong, apparently (big surprise, eh?): 8.0.1.5 saveset ALL 
> worked without an error ...

Well, sorta ... Win2012 and Win2003 worked without problems, using client 
8.0.1.5 to NW server 7.6.2. 1 is a 64bit client, 1 is a 32bit client. All 
worked as expected.

The 2 Win2008R2 clients did not. Same error as before:

* dctrtst007:DISASTER_RECOVERY:\ System Writer - ERROR: Failed to save 
FileGroup files, writer = System Writer
* dctrtst007:DISASTER_RECOVERY:\ System Writer - Error saving writer 
System Writer
* dctrtst007:DISASTER_RECOVERY:\ System Writer - ERROR: Aborting backup of 
saveset VSS SYSTEM FILESET: because of the error with writer System 
Writer.
* dctrtst007:DISASTER_RECOVERY:\ System Writer - Error saving
* dctrtst007:DISASTER_RECOVERY:\ 90110:save: save of 'VSS SYSTEM 
FILESET:\' to server '<NW server>' failed: No such file or directory
* dctrtst007:DISASTER_RECOVERY:\ 90123:save: VSS save walkers: the backup 
of save set 'VSS SYSTEM FILESET:\' failed.

So the backup fails, before it ever gets to any drives. If I bring up the 
GUI to try a directed recover, I see only half the VSS entries I should 
see, no DISASTER_RECOVERY, and no drives. So that error makes the whole 
job fail, it doesn't just move onto the next element to be backed up.

VSSADMIN LIST WRITERS shows no errors, and all VSS WRITERS as stable.  The 
only thing the Windows event log shows is "backup failed". Networker log 
(on client) shows nothing more than the above.

And, of course, all the storage nodes I wanted to upgrade this weekend are 
all Win2008 R2 ... I guess that will be out.

I will try live Tech Support; maybe they can help ...