Warning: Database file needs update - warning: /etc/aliases, line 2: record is in "key: value" format; is this an alias file?

I was investigating an error that I commonly receive in Logwatch every morning.

        2   *Warning: Database file needs update ----------------------------------------------------
        2      /etc/aliases

So I did what any normal person would do and GREPed the logs and ended up with this error:

/var/log/syslog:Jul 30 07:49:41 mx postfix/postmap[11224]: warning: /etc/aliases, line 2: record is in "key: value" format; is this an alias file?

So I did what any admin would do and ran newaliases, however that produced this error:

/var/log/syslog.1:Jul 29 17:03:48 mx postfix/smtpd[4062]: warning: database /etc/aliases.db is older than source file /etc/aliases

So after doing several Google searches I ended up finding a forum that gave me running this as a solution:

postalias /etc/aliases

That seemed to fix the problem. I could run newaliases after than without any error.