How do we enable end users and / or their administrators to recover licenses from crashed machines without compromising licensing security?

In conjunction with leased licensing, and with appropriate application integration, your end customer can run your application on a new machine and “hijack” the license from the previous machine. If in fact the machine had not crashed, its license will nevertheless stop functioning.

Alternatively, the administrator, who may be your administrator or your enterprise customer’s administrator, may (if granted the appropriate privilege) free the license on the server so that the end customer can reactivate it on another machine.