error MT0117: Can't launch a 32-bit app on a simulator that only supports 64-bit apps (iPhone 6s)

Question

Using Xamarin.Forms, Visual Studio 2017 on a PC, and MacBook Air for building the mobile application to iOS.

Yesterday, I updated the Visual Studio version to 15.3.5. I also updated the MacBook Air (via VS for Mac) to get the latest version of iOS (11.0). I created a new app (Xamarin.Forms) just to test the update and everything worked as expected.

I tried to run an older app that I was developing previously, and I wasn't able to run it on the Mac.

I got the following error:

Launch failed. The app 'AppName.iOS' could not be launched on 'iPhone 6s iOS 11.0'. 
Error: error MT0117: Can't launch a 32-bit app on a simulator that only supports 64-bit apps (iPhone 6s). Please check the logs for more details.
The app has been terminated.

Next, I plugged in a device (iPhone) to the Mac and tried to run the application to the device. I was able to run the application, but I got a message notifying me that the application will stop running as soon as I update the iOS of the Device (I didn't update the iOS on the device).

So, the question is how do I solve the problem? Does this has something to do with my application, or the packages that I'm using? Is there a setting that I need to set? Is it possible to run an old simulator on the Mac?

Answer 1

If you change the support architectures to "i386 + x86_64" or "x86_64", it should solve your problem.

You can right click your project -> properties -> iOS build -> change "Supported Architectures" to "i386 + x86_64" or "x86_64"

Answer 2

With Xcode 9 it should be possible to install simulators back as far as iOS 8.1 - a least that's what the "Components" tab says in the Xcode preferences.

I don't use the simulators regularly since at my company we have a couple of test devices with all our supported iOS versions and i trust testing on actual hardware more than testing on simulators.