Can anyone recommend the best way to recover data from a drive being used by a DNS-323?
On Windows, download and install EXT2FSD.
http://www.ext2fsd.com/When given the option, choose to mount drives in "Read only" mode. This will prevent any accidents.
Attach your hard drive from the DNS-323 to your computer either directly, or via a SATA/USB cable or enclosure.
Run the Ext2 Volume Manager application. You should see and be able to assign drive letters to partitions on the drive.
I previously used "EXT2IFS" as it was simpler, but it doesn't run on Windows 7. EXT2FSD does the job, but if any of your files or folders contain special characters, EXT2FSD will screw the filenames up. I've also had a BSoD (Blue Screen of Death) using this application.