Xcode 9: Could not attach to pid

Question

I\'ve been facing an issue (frequently) with the recent major release of the iOS application development tool - Xcode 9-beta.

It\'s showing me the following error fr

Answer 1

First, close app completely via sim (not sleep - close app totally) If not working yet: reboot whole PC, ensure only 1 simulator is active upon reboot.

More than 1 sim can confuse it if it's bugging.

Answer 2

In my case (Xcode 10.1), this was the error in the console:

kernel  macOSTaskPolicy: (com.apple.debugserver) may not get the taskport of (bin) (pid: 10132): (bin) is hardened, (bin) doesn't have get-task-allow, (com.apple.debugserver) is a declared debugger

So the solution was disable the Hardened Runtime, clean the build folder and run again.

Answer 3

I had this issue too. There seems to be an issue with having two Xcode version installed at the same time. (9.4.1 and 10.0 Beta)

It works with the beta, but not with the stable version. Everything is set to the tools of the Xcode 9.4.1 stable version. I can only run my unit tests with the beta.

After removing the beta, it worked with the stable version.

Answer 4

(most likely solution) 1. Simulator-> Hardware-> Erase all contents and Settings

(less likely solution) 2. keychain-> upper right lock-> unlock and lock again (or the other way around)

Answer 5

This happens on my machine, when I set the 'new build system' Go to menu file=>workspace settings and set Build System to "Standard".

Answer 6

Still not a permanent solution, but I had to quit and restart Xcode as the other solutions did not work for me.