Just an FYI for any of you Kestrel 4500NV w/Bluetooth owners.
My Kestrel 4500NV w/Bluetooth freezes and the control buttons have no effect on the operation until the battery door is opened and closed, a hard reset. After the battery door is opened and closed the unit functions normally for a while, but will freeze again or not turn on after it has off for more than a week or so.
I just got off the phone with Nielsen Kellerman Tech Support and they have a software fix for this issue.
Anyone with similar issues should contact them for an RA number.
Tech Support representative Ben Nielsen Toll Free: 800-784-4221