This applies to browsers that use the HOSTS file and to all versions of Windows.
I run HostsMan V4.1.96 to add thousands of websites for IE10 to block via the HOSTS file. My HOSTS file update sources are shown in the attached pic. When HostsMan updates the HOSTS file, it optimizes the layout with multiple URLs on each line such as shown below. In this case, HostsMan is placing 9 URLs on each 127.0.0.1 line.
127.0.0.1 omn.sonypictures.com metrics.sonystyle.com metrics.southwest.com metrics.starwoodhotels.com omniture.stuff.co.nz stats.style.com metrics.sun.com metric.superpages.com metrics.superwarehouse.com
127.0.0.1 om.symantec.com metrics.syracuse.com omtrkpix.tasteofhome.com metrics.tbs.com metrics.teambeachbody.com o.techworld.com info.telstra.com hits.terra.com mtr.tfponline.com
127.0.0.1 metrics.theatlantic.com metrics.theb2bt.com metrics.thedailybeast.com sc.thedailyshow.com metrics.thefrisky.com omniture.theglobeandmail.com analytics.thesmokinggun.com n.thestar.com www33.thestreet.com
If I open the Norton main GUI and go to SUPPORT>Get Support, NIS V21.0.1.3 runs a check of my NIS installation. As part of this check, the HOSTS file is examined. NIS finds that URL om.symantec.comstats.norton.com are in the HOSTS file. The Norton Autofix deletes the entire string of URLS instead of just om.symantec.com and stats.norton.com ":
127.0.0.1 om.symantec.com metrics.syracuse.com omtrkpix.tasteofhome.com metrics.tbs.com metrics.teambeachbody.com o.techworld.com info.telstra.com hits.terra.com mtr.tfponline.com
The Norton Autofix also finds stats.norton.com
127.0.0.1 stats.nomade.fr stats.norton.com stats.ourstats.de stats.profileponds.com stats.sitegauge.bizland.com stats.skyhorn.com stats.speedclicks.ero-advertising.com stats.superstats.de stats.superstats.nl
So instead of removing 2 URLs, it is removing 18 URLs.
This bug is in the Autofix used by NIS V21.0.1.3; however, I suspect it affects all versions of NIS, NAV, and 360.
I have attached the HOSTS file before the Autofix incorrectly "repairs" the HOSTS file and also the HOSTS file after the Norton Autofix improperly "fixes" the HOSTS file.
The Norton Autofix needs to be modified so that it can properly handle HOSTS file structures that have been optimized with multiple URLs on a single line.
I have uploaded to TinyURL.com and SymNRA logging file named Unknown4987d698.zip, reference siliconman01-03 that contains a run of this Norton Autofix that improperly modifies the HOSTS file. Hopefully this can be resolved/fixed.