I have bought the hmm2 here on GOG, and I would like a fix, so that EDITOR would work as well

The game specific board would be a better place for this topic.

Which is located here: http://www.gog.com/forum/heroes_of_might_and_magic_series#1375764210

I don't have the GOG HoMM2, but almost everything can be solved by installing it outside of Program Files (or another protected space like Windows or My Documents). Install it by running the installer as an admin. Run the program as an admin and in a compatibility mode. And see if the editor has its own exe.

Also, you may want to write to Support.

Have a great time with HoMM2! I loved it back in the day.

I tried that but it does not work, I even tried to put it dosbox but it was so slow that it just didn't make any sense to play. I'll write some more in support. Tnx all

Try hitting ctrl+F12 a few times in dosbox, until you get a comfortable speed.