I did notice this yesterday, too.
Same scenario with same NAS (but I don't think this issue has anything to do with the Buffalo).
Once incrementals have been added, you will see them on the drive, but not available for restore in SP unless.... you restart your Windows.
Then they will magically appear there in SP.
This is weird, to say the least, and am starting to doubt I did a good purchase yesterday after reading some positive comments on WildersSecurity.
I should have actually tested it myself rather than rushing with the purchase.
This weird thing of the disappearing backups, together with the inability to backup directly to DVD disks as well, uhm....
Also, can you please confirm whether your backups can be successfully validated in SP?
In my case some of them are ok, some others fail with no apparent resons - CRC errors and such.
I am using Vista Ultimate x64 SP1 with an Intel Pro 1000 Desktop and a Gigabit Linkstation Live connected through a Netgear switch.
Both the pc and the NAS have 9K Jumbo frames enabled so SP can do backups nicely fast (~40MB/sec), but the fact that not all backups/incrementals validate successfully is worrying me a little.
@staff, is there anything in my configuration which might explain corrupted images, CRC errors?
Apart from with SP, I have no problems at all with network transfers.