We enforce content protection, however allow the address book to be excluded so it can be used while locked. There are some users that when they lock their device and contect protection encrypts the data, they lose access to half of their contacts. I've wiped the device and still no fix.

... and they can access everything when unlocked?

yes, they can view them unlocked. It seems about half of their contacts are unavailable once locked.

What version of BES are you using? and this problem is only with 8830 users? what about 8700 series or others?

we are using 4.1.3.16 and it is only with the 8830. I finally responded to your post after it has been brought up again by angry users. I just removed the user from the BES and wiped his 8830 and reactivated and it still does it.

Are any of the 8700s or any other devices / users using 4.2 Handheld OS software?

No, they 8700s are still on 4.1 (no update from Verizon). 8830s are on 4.2.2.66

Sounds like a policy / device thing. Check out the policy reference guide to see what would be specific to 4.2.

I tested Content Protection with my 8830 and BES 4.1.4 and did not see any of this. I'm almost positive I applied the content protection to the addressbook. I neve saw a loss of contacts, but Caller ID did not work when the device was locked and that is a by design function (as it appears). I see the benefit for the data at rest encryption that content protection provides, but it is a pain to deal with as well. That is the problem with increasing security, as security goes up usability goes down.