Shoutbox

If you have forgot the password to your Plus! preferences read below:

You will delete a "key" and it will remove your password so you will then have no password for your preferences.

Go to Start  > Run



Type regedit and press Enter.

Navigate to: HKEY_CURRENT_USER > Software > Patchou > Messenger Plus! Live > (your@emailaddress.tld) > Preferences.
Do this by clicking on the folders on the left hand side.

In Prefrences delete the key labeled PreferencesLockPwd. By selecting the key and pressing the delete button.

After that there will be no password for your preferences.

Be VERY careful when editing the registry! (you can mess up things if you do the wrong thing.

There already exists a much better explanation. Not to mention you didn't mention that this doesn't turn the password setting off, just removes it
CookieRevised's reply to Preferences Password