[SOLUTION] Android Error - Trusted Credential Store Password

   While installing an encryption certificate from my email provider on Android, my phone suddenly asked me to "Type the password for credential storage".  I have never set a "credential storage" password or installed a certificate before, so this seemed very strange.  I tried my lockscreen password, 0000, 1111, 1234, etc...but nothing worked.

    With a little persistence, I decided to clear my lockscreen password to nothing and then try to install the certificate again.  My device prompted me to set a 'new' lockscreen password, which I did and then the email certificate installed successfully.

Bingo!

P.S. - My email provider uses Exchange ActiveSync as their backend...if that matters.