Mac OS is dropping support for 32-bit apps. Pico-8 0.1.11g's Mac build is currently a 32-bit app. In High Sierra 10.13.4 (a recent update), starting Pico-8 now opens the new "not optimized" dialog that indicates this condition.

At this moment in time I am running dozens of apps, from big windows to small menu helpers. Every single one of them is already 64-bit. The only 32-bit app I could find one time when I checked was parts of Apple's own QuickTime.

There may be a few apps that I only use occasionally, but I'm sure I can find alternatives for those.

Anyway, it would be good for Pico8 to be updated to 64-bit before September.

Agreed, hopefully next pico8 update will bring 64bit support.

Likewise - nothing like a deadline to focus Zep's mind! :D

Another vote from me for the recompiled 64 bit Pico. About two months away from the macOS 64-bit update.

Update: macOS Catalina was just released, which means PICO-8 will break for anyone who updates.

Microsoft is too forgiving and Apple is way too strict regarding backwards compatibility. Still mourn my 32 bit iPad Games.

The Mac build of PICO-8 0.1.12C is 64-bit, so this issue is resolved. Anyone on an older version just needs to update to the latest.