Help Face unlock option greyed out

[carlt0n]

I have an HTC One S 4.1.1 Sense 4+
I was using face unlock or PIN when it didn't recognise me (most of the time).
I wanted to turn this off but find the face unlock option in Security is greyed out and the message 'disabled by administrator, encryption policy or credential storage'.
I now want to turn off the PIN screen unlock and just use the ring.

If I delete all the credential certificates will this allow me to access the face unlock option but will this cause other problems with installed apps?
Or should I use 'Reset Phone'?

 

[leit4444]

Is this a business phone and do you use exchange or a mobile device management? Admistrators can enforce security policies with that.

 

[carlt0n]

No to all those it's just my private handset for calls, hotmail, photos and music etc.

I did a factory reset and this cleared the problem then just re-installed my apps.
All working okay now, there was nothing to be afraid of.