I keep my old Windows XP setup which I revert back to whenever I need to rescue an old project that won't open properly in my current Windows 7 setup. Yesterday, on this XP platform, when I tried to open the Battery 3 GUI in a Sonar project, I got this message:
 
"Your hardware has changed please use the service centre to reactivate..."
 
I have another Native Instruments product, B4II, and I got the same thing with that too.  But the hardware had not changed since last time. In fact there have been lots of hardware changes in the past that have never resulted in any messages asking for reactivation. So I just rebooted and the message didn't come back.
 
Just a glitch I suppose. A strange one though.

I had the same thing about 2 months ago with Kontakt 4 or 5 [can't recall which one of the 2].
 
I didn't change a damn thing - hardware or soft.
 
But sure enough, I needed to fire up the ol' Service Centre and re-activate it.
 
Very strange.

The license is tied to your hardware profile to prevent installation on more than one machine. I hate that. Replace a broken motherboard and everything stops working. It doesn't have to be a hardware change, either: disable the network and everything stops working.

Some times having an external hard drive was enough to upset som program's. I have not had that issue for a long time though. Maybe it's better on newer OS.