We successfully implemented a "Restrict Drives" policy a couple of years ago based on the following article:

http://www.windowsdevcenter.com/pub/a/windows/2005/11/15/disabling-usb-storage-with-group-policy.html

We saw floppy drives and USB sticks disabled. We were happy.

However, in the past few weeks something has happened and this policy is no longer in effect. We learned this after we saw someone using a USB stick. We were able to find the policy, disable it and re-enable it in order to make it functional again. This didn't last, though; as the policy is now no longer effective.

Has anyone else seen similar issues? Is there a Windows Update that's to blame?