Download the ME-2 solver and either contact Dr. Paatero or purchase a license key for ME-2 through Datalystica. Note that the solver alone will not work without the ME-2 key. Unless otherwise specified, the license is a perpetual institution license.
The ME-2 license key should be stored under its original name (me2key.key) in the ME2_engine folder. Otherwise, following error message will pop up.
The ME-2 solver only works in a windows environment. If you are using another system, a windows emulator should be used.