App Quits on Mac

Every time I open up my arduino application, it quits automatically. I'm running on Mac OS X el capitan 10.11.6. Any tips or ideas? I've tried deleting/redownloading and also restarting my computer

Having the same problem here. I had Arduino loaded on my 2015 Macbook (El Capitan 10.11.6) and was using it for the last 6 months. Just yesterday the Arduino icon was replaced by a question mark and no functionality. So I reloaded the app and now it briefly starts up before quitting with the error "Arduino quit unexpectedly". Tried a new download, restart, etc.

You're experiencing this bug:

Arduino IDE 1.8.8 is only compatible with macOS 10.12 and newer.

The recommended solution is to use Arduino IDE 1.8.7 until Arduino IDE 1.8.9 is released. You can download Arduino IDE 1.8.7 here:

The bug has been fixed in the Hourly Build of the Arduino IDE so you also have the option of using that version:

Be aware that the Hourly Build is primarily intended for beta testing and is not as thoroughly tested as the production releases of the Arduino IDE.

thanks so much, that seems to be working

You're welcome. I'm glad to hear it's working now. Enjoy!
Per