Can't change security settings due to VPN setup This appears to be a duplicate of this post, but the solution there didn't work for me. Clearing the credential storage wasn't even an option -- it's greyed out.

Starting at the beginning -- I started to set up a VPN on my phone (Note 3, Android 5.0) but cancelled the operation halfway through, yet the OS still enforced the security settings (a PIN). I have tried a few things trying to disable the PIN lock, but the only option I have is to upgrade the security to a "password" which is even more unacceptable.

So far, I've tried finishing the VPN setup (it worked) then removing it, also force stop/disable of the VPN app, and quite a few other things that I can't recall at this moment. 

I think part of the issue is that a certificate was installed when I started the process, but I have no idea which certificate it was. The System cert list is populated with tons of entries, but the User cert list is completely empty. Is there a way to determine which certificate was installed so I can remove/disable that one? I'm concerned with choosing the wrong one, as who knows what it might break on the phone.
Try this Its an apk that can disable the screen lock. It worked for me on KitKat when I had the same problem.
Install it, select launcher and don't mind the icon.