Mac Password dialog box font missing / corrupt

If you see the old unlock screen (gray window asking for your username and password) you have to delete the following file:

/etc/cacloginconfig.plist

If you delete this file, you will see the new unlock screen (like the login screen) and touch ID will work again.

Summary: If "/etc/cacloginconfig.plist" exists in 10.9 +, the screensaver unlock screen will be controlled by SecurityAgent (old style). Admins, when they successfully authenticate, will be allowed to take over the user's session. Even if "system.login.screensaver" in AuthDB is set to "use-login-window-ui", this will be overridden by the existence of "/etc/cacloginconfig.plist". We will still be presented with the SecurityAgent style login window.

More Info: http://www.openradar.me/19177988

Actually you don't have the correct version of Helvetica in the right spot.

You are missing the files Helvetica.dfont and HelveticaNeue.dfont which are the correct files for the missing fonts. They should be in /System/Library/Fonts. Have a good look at the support page you point to and you will see those two files listed against the fonts.

You do have two files, Helvetica.ttc and HelveticaNeue.ttc, which are not included in a standard Mavericks install but they are not where the System is expecting to find the two fonts.

As an experiment move these two files into ~/Library/Fonts and see what happens (I'd be interested to know the result).

In the long term grab a copy of the two missing files from another Mac running 10.8 or 10.9 and put them into /System/Library/Fonts. You will have to do this by hand since Font Book will only install fonts in either /Library/Fonts or ~/Library/Fonts.