Well, I must say that I am not 100% sure if it actually worked with the Wifi. It did change the MAC-address for the network card en0, which I recently realized is the ethernet card. And I did have the ethernet cable connected earlier. Only later I realized I was not observing it changing the en1 (Wifi) MAC so I don't actually know if it worked with the Wifi or not at any time.
So, IMO it can be one of the following:
WifiSpoof never worked with late 2009 (or late 2010) iMac Wifi card
it did but Wifispoof update caused it to stop working
or updating Mac OS Sierra to High Sierra + possibly one or both things above = not compatible
To recap from our previous discussion, my 3 requests are, in this order:
Ability to reorder windows/tab groups. You mentioned you'd get to that when you have time. Thanks! This is particularly important because I will use the app to store tab groups/windows because I currently have 30 windows open with 10-30 tabs each and it's slowing down Safari. So I'd like to save a session, rename and reorder the tab groups/windows, then close the windows in my current session of Safari. When I need them, I'll go back to SessionRestore and relaunch a given tab group/window.
Add undo (Command + Z) when combining windows/tab groups for example. It would be nice if it functioned on all app actions.
iOS/iPadOS app! That would be amazing to sync these tab groups!
If those three things were added, I think the app would be nearly perfect!
Another item if you feel it's worthy:
Lock left panel SessionRestore session window. It scrolls in all directions.
I have tried multiple apps for restoring and saving sessions and this is clearly the most advanced solution!