Re-install stock Net-SNMP?
The canonical method to reset a net-snmp installation to factory defaults in Mac OS X (there's no difference between client &amp; server in this case) is:

sudo launchctl unload -w /System/Library/LaunchDaemons/org.net-snmp.snmpd.plist
sudo cp /etc/snmp/snmpd.conf.default /etc/snmp/snmpd.conf
sudo rm /usr/share/snmpd.conf
sudo rm -rf /var/db/net-snmp


This resets the snmpd.conf file to the default &amp; clears out any added users and instance data. This should be valid back to 10.6 or so, possibly earlier, but I'm not sure.

In 10.11.x Apple updated the net-snmp version from 5.6 to 5.6.2.1 which may cause some issues.