I must understand that if I don't disactivate lumion before reinstalling windows, Lumion don't work anymore. . But for example if I have a crash of the system, what happens with Lumion. You have the posibilité to reactivate lumion otherwise.
In this case, the Lumion Team can deactivate your license in the background and you can activate it again. An understandable desire on their end that you should do this for yourself on your computer when you are able to however. I've seen them do this server side deactivation even in cases when someone forgot to deactivate it at work but wanted to use it at home during the week-end though so they are helpful it appears.