OSX 10.10 Internet Sharing Password Not Correct

My Mac lost ethernet connection yesterday briefly whilst Internet Sharing was running.

I rebooted, by Internet Sharing wasn't accepting Connections at all.

I deleted the relevant files in:/Library/Preferences/SystemConfiguration/

Rebooted, this cleared out all the settings for Internet Sharing etc

As default, there is no Internet Sharing security set

I turn it back on, no security, but any wifi client that sees it with no security (iPhone doesn't show padlock) but the client asks for a password.

The way it asks for it on the iPhone differs to how it would if it knows the WIFI is password protected.

can someone tell me how to resolve this, there is no password set on the mac internet sharing but clients ask for it? Cheers,

Lee