Changing MAC address caused Windows to need to reactivate itself

[Ben Moerlein]

I changed the MAC address of several machines today, because we ghosted them and they all were using the same MAC address causing serious network performance issues. I change the MAC address by going to network connections Properties ->Configure -> Advanced -> added one for Network Address.

After rebooting with the new MAC address windows came back with a popup message that said the hardware had changed severly since Windows was activated and I needed to reactivate Windows. When I put in my coporate liscense for Windows XP, it didn't take. Any suggestions on how to get past this.

[HGN]

Hi

Are you referring to the IP address? in any case you can unplug the network when the server is coming up change it to the right ip and plug it back in which will not cause any duplicate IP on the network.

Rgds

Gopi

[Ben Moerlein]

That doesn't work....I have tried ipconfig /release and /renew and it still comes back up with the same ip address. It retains the IP address as before because the MAC address that is has is pointing to that IP address.

[jeng033]

Hello Ben,

I cant image, that the MAC address is somewhere stored within windows. The MAC address is an unique ethernet hardware address that is stored within your NIC!

In general I would never, ever enter a MAC address in the MAC address field of the NIC driver, because you can never be sure, that nobody within your segment does have the same.

Using ipconfig should work to determine the MAC address. If it is the case the Windwos caches the MAC address after the clone. I would remove the NIC using the device manager and have it windows find again.

Regards,
Dietmar

[Ben Moerlein]

Guys, thanks for the responses but we figured it out last night.

The NIC cards we are using are built on NICs of a ASUS P4S533-MX motherboard. We found out that the factory drivers for this NIC card have a static MAC address that it assigns to the computer. In order to fix this we had to update the driver to the latest version. At this point the NIC card then used its own unique MAC address, and was able to get a different IP Address.