I did upgrade from 4 to 5 and lost all my setup/targets but rather than spending a lot of time trying to figure it out I just re-entered things and used it as a chance to clean things up. I did not notice a migrate option at the time.

The service account issue was after I had upgraded to V5 from V4 then the next day there was a prompt for an even newer version. That V5 to V5 upgrade cleared out the logon account for the Pingplotter service. Should be easy to reproduce. Oh one thing is we are on a domain and the logon account is a domain account and not local computer account. Maybe that matters.

I can do some testing on if the DNS names get lost or not and report back.