Could not attach to pid : “####” unable to attach [duplicate]

问题

This question already has answers here:

Failed to Attach to Process ID Xcode (34 answers)

Closed last year.

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?

回答1:

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

回答2:

Kill the simulator, then re-build.

回答3:

1. I closed Xcode.
2. On the simulator menu: go to Hardware -> Erase all content and settings.
3. Open Xcode then build and run the application.

The above simple steps worked for me.

回答4:

In my case Xcode 8.0 after this error,just rebuild again project it solves this problem.

There is no need for reset app content in iPhone device.

回答5:

1. Close Xcode & simulator
2. Reopen Xcode & rebuild

Above steps worked for me.

回答6:

Clean the project,quit the simulator and then rebuild the app

来源：https://stackoverflow.com/questions/37582096/could-not-attach-to-pid-unable-to-attach