Not work on macOS Mojave: may have been in progress in another thread when fork() was called.

[fifiteen82726]

forecast = ForecastIO.forecast(37.8267, -122.423)
objc[1684]: +[__NSPlaceholderDictionary initialize] may have been in progress in another thread when fork() was called.
objc[1684]: +[__NSPlaceholderDictionary initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.

[enciie]

export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

[swaathi]

This fix doesn't work on Mojave. It does the trick on High Sierra though.

export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

run this in terminal

[fblupi]

Same problem here. Even adding the env variable above

[sourabharsh]

It worked

export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

run this in terminal

It worked for me on Mojave. thanks a lot!

[reekoong]

export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

Worked for me

[marc-wilson]

Running

export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

does not work on Mojave

[marc-wilson]

Not to revert my previous comment, but I actually did get the export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES environment variable to work. The problem was that I was running the command in the terminal. It won't work there.

In my case, I use PyCharm with a virtual environment. After adding the environment variable directly in my build/debug configuration under environment variables, it worked like a charm:

I'm not sure if this is something that's specific to my setup, but doing it this way worked for me.

[coisnepe]

Doesn't seem to work in Catalina...

[jakubmuransky]

Doesn't seem to work in Catalina...

Same here, stop working on catalina, stuck on Gathering Facts

[gbudiman]

FWIW, I landed on this page while googling the exact same error message caused by different gem (google-cloud-ruby). I downgraded ruby from 2.6.5 to 2.6.3 and the error went away. I'm on Catalina. Take this with a bucketload of salt though.

[benkruger-neyborly]

Super stuck with this with Catalina :(

[Arpanbhalla]

Stuck with Catalina too