Every three months or so I use Norton Ghost to make a copy of my main C drive onto a separate hard drive for safety. I always boot up the copied drive to check and see if all is okay with it. It always is.
The only thing odd I notice is that Avast! gives me a warning that it doesn’t have a valid license when I boot up the copied drive. This isn’t a real problem, as I’ve never had an emergency where I had to use the copied drive and I use the free version of Avast! so all I’d have to do is ask for a valid license number to get it running on the copied drive.
The question is; how does Avast! know it’s running on a different drive? If I’ve made an exact copy of the first drive, shouldn’t the environment be the same as far as the installed software is concerned? Does software like Avast! take note of some physical properties of the particular drive on which it is licensed or what?
Some licensing schemes use the hard drive serial number (or network card MAC address, etc) to generate their code, so as to tie the license to 1 computer only. I’ve only seen that on obscenely pricey applications though, I didn’t know Avast did that.
One email to customer service should fix it though.
As mentioned, the serial number on the cloned drive is most likely different.
More geeky details: On a Windows box, this “serial number” is actually stored in the file system, and not reported by the hardware. All the drives in a Windows system MUST have a unique file system serial number, or Very Bad Things will happen. Your cloning software must be aware of this and must have generated a new serial number on the clone. I’ve tried to clone a Windows drive myself by hooking it up to a Unix box and doing a “dd”, thus producing a truely identical clone. Things went very wrong when both the original and cloned drives were present in the system at the same time. This was many years ago and I have forgotten the specifics, but basically Windows was confused about which drive was which, and it turned out quite badly.
It’s reading the drive hardware to find it’s not on the same drive. I’ve also had that software tell me the license is not valid, because I changed the processor speed with the clock in the BIOS. That software checks a number of hardware parameters to see that the license belongs to the computer.