Old version of Toolbar reappears as a Chrome Extension

I noticed that Identity Safe stopped entering ID's and Passwords for sites that had them set up, and for which the Identity Safe list showed their existence.  After several failed to be filled, I looked for answers, since getting Symantec replies for this "failure to fill" problem never happens.  I noticed that an older version of the Toolbar was active in the list of Chrome ( Version 53.0.2785.101 m) extensions, along with the current Norton Toolbar version ( 2015.7.0.69).  I removed the older one and the problem went away.  A day later, after a restart, the old extension ( a "2014..." one) was again listed and enabled.  I "trashcanned" it again.  Is there a way to find the source of this problem to prevent recurrence?