Update Wineskin, disable SIP or wait until GOG updates the Mac build.

Updating Wineskin worked. I'd already disabled SIP. Thanks. :)

No news from GOG on this?

Please, GOG!

Any news ? Also I was unsuccesfull with wrapper update and rootless. Any idea ? Maybe something litle that i miss?

Not buying any more from GOG until they fix this.

Some games are cheaper here than on steam but I'll not put a single dollar in this company until they take care of existing customers.

I was so happy this game was available (I bought the original for windows and for linux!).

Making users disable security settings or patching anything themselves is not serious.

How it's GOG's fault when OS developer introduces features that makes previous software incompatible with it? Be glad that GOG at least does it's best to support new operating systems with it's older titles. On Steam you're on your own if developers have moved on. Steam won't lift a finger to ensure compatibility. Heck even numerous games in development have problems adabting to new operating systems.

Disabling security is temporary workaround till GOG can find, test and apply appropriate settings and fixes to their installers while making sure they don't break compatibility with other supported systems. From updates I'm getting GOG is updating Mac builds at around 3-6 games per day so barring game specific problems, they should get to this one eventually.

On windows side UAC (user account control) still gives problems with some games (even new ones) and configurations 10+ years after it's introduction in Vista. Most people just avoid the hassle by installing outside program files folder and/or running games as administrator bypassing "protection" it gives. MS discourages this but cost of reprogramming a pre Vista game to follow rules that did not exist at time of development is too costly for most devs to even consider. GOG installers these days actually apply both workarounds to give games best change of working as intented.

There are also plenty of games you still have to apply various workarounds to make them reliably different systems, workaround that may cause problems on others. That's just how PC gaming is and has always been. There's simply too many hardware, software and driver configurations to provide universal one-size-fits-all solutions to all games and configurations.

Is someone at GOG aware of this problem? I don't mind waiting, but it feels like it's on nobody's to-do list...

If you've been following The "what did just update?" thread or otherwise checked games that have been updated lately, you should've noticed that many games have been receiving following updates in their changelogs: So yes, GOG staff is aware of SIP problems and are working on fixes as I already mentioned above. But with some 600+ MacOS titles in catalog it'll probably take awhile to go thru all of them.

Meanwhile you can use Gydion's workarounds posted above.

Then we'll play... the waiting game.

And here it is (along with similar patches for at least Nox and Jagged Alliance 2):

The game still doesn't work. :/ It'll launch, get to the screen where it asks whether you want to play Alpha Centauri or Alien Expansion, and when you make a selection, it crashes.

Hmm, maybe yours is not related to problem introduced by El Capitan but previously encountered intro movie (or apparent lack of Alpha Centauri.ini) issue mentioned in another topic?

I think you should contact GOG support. Maybe GOG techies can provide you MAC specific workaround or produce a fix for it.

I've reached out to them, and we'll see what they can figure out, but the problem arose after I installed El Cap and the new version of AC.