NAV changed my HD name

I just installed NAV and ran a manual scan first.  I stopped the scan after it had run for 18 hours.  Initially it had said there were just over 2 million files to scan.  By the time I had stopped it, it had scanned over 16 million.  It also had changed the name of my hard drive from MAC HD to something like lhkllglghellh.

 

I am running a 2011 iMac 27", 2.7 GHz running OS 10.6.8 with 4 GB RAM, 1 TB internal HD and a 2 TB time machine backup drive.  I was having it check only the internal 1 TB drive (which has 911 GB free).

 

What can I do to prevent these errors in the future, or is this a "feature" of NAV?