Cannot change screen lock setting I'm using Android 4.3, and a few days ago I added a new root certificate to my phone (Via Settings > Security > Credential Storage / Install from storage). This required me to choose a screen lock pattern or PIN. So far so good.

Now I've removed the certificate, but I can't change back to using swipe to unlock. The option is disabled, with this message:


  Disabled by administrator, encryption policy, or credential storage


To be clear:


There are no options selected in the "Device administrators" settings page
Encryption has never been enabled on the device
There are user credentials stored on the phone (The "User" tab of Trusted credentials is empty)


Is there any way of finding out what is preventing Android from enabling the swipe to unlock feature?
Just from my readings, I think choosing the option to clear credential storage (removes all certificates) may allow swipe. Even if there are no certificates, you may need to explicitly use that option to clear certificates.