Q:

Could not attach to pid : “####” unable to attach

I just updated to Xcode 7.3.1 and my project crashes with the same error after the launch screen displays on the iOS simulator. 
The error is:

"Could not attach to pid : “1712” unable to attach"

Then I tried running another project and I got:

"Could not attach to pid : “2025” unable to attach"

Any solutions? 

A:

Resetting the content and settings in the simulator worked for me. This is available on the iOS Simulator: Hardware -> Erase all Content and Settings

A:

Kill the simulator, then re-build.

A:

I closed Xcode.
On the simulator menu: go to Hardware -> Erase all content and settings.

Open Xcode then build and run the application.

The above simple steps worked for me.

