Lock not working on Fuze+ MP3

My brand new Fuze+ has version 02.38.06A installed and it still will not lock

Can anyone tell me how I can get my Fuze+ to do this as it is very sensitive and is skipping about all over the place

I assume this version is higher than the recommended 02.37.01 

Your Fuze+ has the latest firmware update already installed. The locking procedure was changed with the 1st update after the player came out to the power button. Press it for about 1/2 second to lock it. Same to unlock it.

Unfortunately this info apparently has not been updated in the Quick Start Guide or User’s Manual.

Many thanks, Tapeworm. I accidently discovered how to unlock when the gold padlock came on the screen