launchctl "nothing found to load"

When you get the error "nothing found to load" after running launchctl load. For example:

$ launchctl load ~/Library/LaunchAgents/org.virtualbox.vboxwebsrv.plist                                                
nothing found to load

First check to make sure the package isn't listed as disabled in the global overrides file:
/private/var/db/launchd.db/com.apple.launchd/overrides.plist

If the package isn't listed in the overrides file, launchd documentation offers another file it may be located in.

First get your user id by running id on the command line:

$ id -u
201

Now use this id to find the file:
/var/db/launchd.db/com.apple.launchd.peruser.201/overrides.plist. The override entry should be listed in this file.

In the example given above for virtualbox, you would remove these lines from that overrides.plist file:

<key>org.virtualbox.vboxwebsvc</key>
<dict>
  <key>Disabled</key>
  <true/>
</dict>