For those of us that test products on Operating Systems, but don’t want to use up our activations granted to us via an MSDN or other matter, there is an undocumented way to extend your Windows Vista install to 120 days without activation. Combine this with VMWare reverts and you are good to test the OS without activation.
Microsoft kept an unadvertised feature in Vista activation. By default, unactivated Vista or Vista installed without any key will run up to 30 days before it deactivates itself.
The unadvertised feature is a command called:
slmgr -rearm
This resets the Vista counter back to 30 days. You can do this 3 times. To run unactivated Vista as long as possible in testing, you run the command the day before Vista expires like on the 29th day, and the counter will reset back to 30 days. If you timed it right, you can have almost 120 days to test your Vista without having to waste a license.
Since this is a built-in feature of Vista, it should be legal since we are doing it for testing anyway.
Also a method to check how many days the Vista still has before it expires is properties on the Computer. The commandline method is slmgr -dli.
This trick still works after the Vista has expired pass 30 days. You get one chance to do it. Reboot Vista and you will get one grace login, but it will keep reminding you that Windows is not genuine. Run that command, and reboot again. If it works, your Vista has another 30 days. If you don’t run that command after the it expired and the one grace login, it will lock you out. Your option is either reinstall Vista or activate the license.
WinXP activation seems to “reset” the usage counter after several months. I don’t know if Vista will let you do that.
