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 frequently while running/debugging app in Simulator (iOS 11).

Could not attach to pid : “2370”
Ensure <project title> is not already running, and <system username> has permission to debug it.

Here is a snapshot for the same issue:

What would be permanent solution of this issue, as it's disturbing frequently?

Can you file a bug on this and attach the output of `sudo sysdiagnose -q` and `xcrun simctl diagnose`? — russbishop, Jun 28 '17 at 06:50
@russbishop Reported a bug. Command 'xcrun simctl diagnose' not working. Error: Unrecognized subcommand: diagnose — Krunal, Jun 28 '17 at 09:45
you must have an older version of Xcode selected with `xcode-select`. Make sure Xcode 9 is selected. — russbishop, Jul 03 '17 at 05:01
I cleaned the derived data & cleaned the build folder. It worked for me. — iOSDev, Oct 05 '17 at 02:23
@russbishop i am also having in 9.4 when i am running test cases how will solve it please help — TheCodeTalker, Sep 26 '18 at 09:52
Check this link https://stackoverflow.com/a/57848546/1753005 — Jayprakash Dubey, Sep 09 '19 at 06:01

ninja_iOS · Answer 1 · 2019-01-30T10:51:51.187

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If issue is on OS Mojave and you are trying, like me to run tests on older Xcode version (lower than 10.0), make sure that in your scheme, when you select Test, Debug executable is disabled

You won't be able to debug tests from this point

edited Jan 30 '19 at 10:51

answered Oct 17 '18 at 13:11

ninja_iOS

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That works, but then you can't debug your tests anymore :( – electronix384128 Oct 25 '18 at 21:49
Unbelievable! Thank you! – Camilo Aguilar Dec 14 '18 at 00:21
This fix also worked for me when I had an "attach failed" error running UI tests on Xcode 12.1 on Catalina. – Angela Nov 12 '20 at 15:58
I have since turned Debug executable back on, and the error didn't come back, and I can debug my tests. So perhaps it only needs to be turned off and on again. – Angela Nov 13 '20 at 00:02

score 23 · Answer 2 · edited May 13 '19 at 16:19

23

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

edited May 13 '19 at 16:19

shim

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answered Nov 17 '17 at 18:46

PicklesIIDX

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damn.. was just a restart :S – Juan Saravia Feb 23 '19 at 02:32

Efren · Answer 3 · 2018-09-04T08:26:38.527

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This worked for me:

Edit Scheme -> Info -> Executable -> Ask on launch

Credits to @nastya-gorban's answer here

Update

After spending a considerable time with examples on Apple bug report, they basically disregarded the issue as using manual certificates is not "expected".

Long story short, if you don't have a business account and hence multiple developers on the same account, you should be fine with using the automatic signing and should not see the issue.

If you do have a business account with multiple users (which I found it breaks automatic signing), this is their suggestion:

We suggest that you use automatic signing for your debug builds and manual signing for your distribution builds.

edited Sep 04 '18 at 08:26

answered Jun 20 '18 at 05:33

Efren

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I have since posted the issue on the Bug reporter, but still interchanging info to figure the cause. – Efren Jul 24 '18 at 04:28
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According to apple: "You can’t debug something provisioned with an ad-hoc distribution profile. Distribution profiles don’t allow debugging...We assume you’re using manual signing. If you selected a distribution signing certificate, then you can’t choose a development provisioning profile. Development provisioning profiles don’t contain distribution signing certificates. So, if you want to debug, you’ll need to select a development signing certificate and a development provisioning profile. Incidentally, this is what automatic signing would have done for you without all the fuss." – Efren Jul 27 '18 at 07:25
Latest and final reply: "Engineering has determined that this issue behaves as intended based on the following information: Yep, depending on which OS we're talking about, the rules are stronger for debugging a process. Ask On Launch is also potentially finding a different copy of the application, so, even on newer iOS versions there may be a way to get something running via "Ask on Launch" if it gets the distribution signed copy. We suggest that you use automatic signing for your debug builds and manual signing for your distribution builds." – Efren Sep 04 '18 at 08:22
11.3 Worked for me – Zeeshan Mar 26 '20 at 17:21

score 11 · Answer 4 · answered Oct 17 '17 at 09:36

11

Killing my simulator and then running it again from Xcode.

answered Oct 17 '17 at 09:36

user2421755

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I tried all these solutions, but it solves error temporary. Can i have its permanent solution? – Krunal Oct 17 '17 at 09:37

score 8 · Answer 5 · answered Jul 02 '18 at 12:49

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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.

answered Jul 02 '18 at 12:49

3

This sounds like my issue. I installed Xcode 10 and updated to Mojave. Then I had to use Xcode 9.4 again and it started complaining like this. I will try uninstalling Xcode 10 and see if that helps. – jowie Sep 28 '18 at 15:03

score 7 · Answer 6 · answered Oct 16 '17 at 16:03

7

delete derived data and clean the project, wait until processing is complete, this may take some time. The idea is to give some processing time. Works fine after that

answered Oct 16 '17 at 16:03

Divya

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I tried that solution, but it solves error temporary. Can i have its permanent solution. – Krunal Oct 16 '17 at 16:54

score 7 · Answer 7 · answered Feb 01 '18 at 19:52

I have been dealing with this issue for days. I have been able to build but not launch on Simulator, and I get the same "pid:.." error message.

I am using: - Xcode v9.2 - Swift 3.2 - Building for iOS

The things that I tried that DID NOT WORK were:

restarting the computer; deleting content and settings (of Simulator, I do not have "reset"); uninstalling and reinstalling Xcode; changing "Deployment Target"; changing the device in the simulator's Hardware->Manage Device; deleting Derived Data, Cleaning and Building, or just waiting...forever.

What WORKED was as @Rajasekhar mentioned:

checked out the Keychain certificates.
deleted the exiting ones by right clicking (they'd passed expiration)
and unchecked "automatically manage signing" in Targets->General

After that it successfully launched in Simulator. I don't know if the issue will come back but hopefully this works.

Please don't add "thank you" as an answer. Once you have sufficient [reputation](https://stackoverflow.com/help/whats-reputation), you will be able to [vote up questions and answers](https://stackoverflow.com/help/privileges/vote-up) that you found helpful. - [From Review](/review/low-quality-posts/18695999) — Gilles Gouaillardet, Feb 02 '18 at 04:12
i included an extra step that i took as well as how to delete the certificate which was not mentioned above but was asked by another user — tameikal, Feb 03 '18 at 04:52

score 7 · Answer 8 · answered Feb 28 '20 at 06:25

Even on Xcode 11.1/2/3

It is an Authorization issue with Simulator, When Simulator does not have the necessary access. It raises the issue.

Try following in Terminal

sudo DevToolsSecurity -enable

or

sudo /usr/sbin/DevToolsSecurity -enable

Details can be found here

score 5 · Answer 9 · edited Aug 14 '18 at 15:31

~~I hate to add more noise to this~~, but for me, the answer is to, nonsensically, use sudo.

Run normally, Xcode 9.4.1 (9F2000) and Xcode 10.0 beta 4 (10L213o) both failed to attach to my app after multiple tries, giving the error quoted in the original post.

What worked was to run Xcode (9.4) with sudo,

sudo /Applications/Xcode.app/Contents/MacOS/Xcode

I don't see why sudo is necessary. The Cocoa app to which I am attaching is a Debug build that I just built in Xcode 9.4.1 and dragged into /Applications. It is not codesigned. Posix permissions on the .app, its Contents, its MacOS, and the executable are all octal 755. Owner is me. It works fine if I leave it in the Build folder, build and debug in the normal way.

The problem is apparently with lldb. I also tried using lldb (lldb-902.0.79.7) from the command line. I got the same result. It works only with sudo. Without sudo,

error: attach failed: unable to attach

This looked like a sound solution, so I held high hopes for it to work for me! Sadly it didn't. I do have two versions of Xcode installed, however. I will try removing one. — jowie, Sep 28 '18 at 15:04

Jayprakash Dubey · Answer 10 · 2019-11-12T06:14:02.497

5

I had same issue. Check screenshot.

Below are few solutions that should work:

Rerun project
Clean (Shortcut: cmd + shift + K) and Rerun project
Quit Xcode and Simulator. Open project and run again
Reset content of Simulator (Select Simulator -> Goto Hardware tab -> Erase All Content and Settings…) and rerun project.

Solution 4 worked for me.

edited Nov 12 '19 at 06:14

answered Sep 09 '19 at 05:59

Jayprakash Dubey

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score 4 · Answer 11 · answered Oct 06 '17 at 14:19

4

This seems to be a temporary issue when you are trying to build too fast after a build has started. Try stopping and running the project again.

answered Oct 06 '17 at 14:19

Tamás Sengel

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Yes, it is temporary. But facing often, with different PIDs> There isn't permanent solution to it? It works fine, "Stopping and running again". But not gone forever. – Krunal Oct 06 '17 at 14:19
1

No, not yet. Seems like it's a bug. Try running only once and don't click several times on the button. – Tamás Sengel Oct 06 '17 at 14:21
2

Yes, I raised a ticket in Bug Reporter for the same. But Apple is unable to track a bug. I shared a complete system report generated using command `xcrun simctl diagnose` and forwarded to Apple. – Krunal Oct 07 '17 at 02:42
Exact!, for me that is due to an excessive time waiting for emulator response – Josem Jun 26 '18 at 12:44

score 4 · Answer 12 · answered May 07 '18 at 20:00

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)

answered May 07 '18 at 20:00

Will Gwo

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Can you elaborate on: "keychain-> upper right lock-> unlock and lock again (or the other way around)". Keychain App? – andrewmclean Jun 24 '19 at 22:37
I think the UI of Keychain Access has changed after this answer was posted. Basically you just right click the lock and click unlock/lock so that it refresh the keychain. – Will Gwo Sep 10 '19 at 22:39
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This has solved my issue. Using Xcode 9.2 on High Sierra. – Mycodingproject Nov 14 '19 at 07:00

aone · Answer 13 · 2022-11-24T09:04:25.357

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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 to disable the Hardened Runtime, clean the build folder and run again.

edited Nov 24 '22 at 09:04

answered Mar 13 '19 at 08:26

aone

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score 4 · Answer 14 · answered May 13 '19 at 16:57

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I was seeing this in Xcode 10.2 and the cause for me was that lldb-rpc-server was crashing. I worked around it by ensuring either Address Sanitizer or Thread Sanitizer is enabled in the debug options. I also filed a bug report viewable on Open Radar.

answered May 13 '19 at 16:57

Rudedog

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score 4 · Answer 15 · answered Apr 01 '20 at 15:05

4

I tried all the answers above. The only thing worked to me is changing the build number.

answered Apr 01 '20 at 15:05

mahdi

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score 3 · Answer 16 · answered Oct 26 '17 at 01:41

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This is the issue with the untrusted certificates in key-chain access, please remove such a type of certificates and re-build again.

answered Oct 26 '17 at 01:41

Rajasekhar Pasupuleti

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How can I remove certificate, can you please eleborate in detail? – Krunal Oct 26 '17 at 04:02
open key-chain access -> check for the certificates, there you can find certificates those not related with your protect. (typically what I'm trying to tell you is? 'some times you open unknown certificates into your key chain access, those are related with your project only but currently do don't have any membership on those teams') – Rajasekhar Pasupuleti Oct 26 '17 at 05:02
One more suggestion is Just kill the Xcode and Simulator, turn-Off your device and restart again,I believe this will fix the issue. – Rajasekhar Pasupuleti Oct 28 '17 at 10:36
We can achieve it by re-starting device & Xcode once. – Rajasekhar Pasupuleti Dec 11 '17 at 19:08
None of the solutions posted here are working at all for me. I've even restarted my computer several times. I can currently only run on a real device. Any updates? – n8tr Dec 21 '17 at 23:04

score 2 · Answer 17 · answered Jun 27 '18 at 06:15

2

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

answered Jun 27 '18 at 06:15

ThorstenC

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score 2 · Answer 18 · answered Oct 03 '19 at 13:58

I realise this is not a problem with a single solution, from all the other answers. So, here's what worked for me:

1) Reboot the machine

2) The first run always works for me. The only thing that helps me avoid this error after this first run, is to stop the application from XCode, instead of just clicking the Run button to re-run the application.

Another thing, when I lock my computer the issue re-appears sometimes (probably when I forget to stop the application). So I have to reboot my machine again.

score 1 · Answer 19 · answered Jul 30 '19 at 21:06

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After doing some digging, this worked for me on Xcode 10.3.

sudo /usr/sbin/DevToolsSecurity -enable

answered Jul 30 '19 at 21:06

Will

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score 1 · Answer 20 · answered Jul 31 '19 at 14:02

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In my case the only thing that worked was switching back from the "New Build System" to the "Legacy Build System" in the Workspace Settings. Bummer.

answered Jul 31 '19 at 14:02

Rivera

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score 1 · Answer 21 · answered Dec 13 '19 at 13:01

1

It's an issue with authorization. Try this in the Terminal:

sudo DevToolsSecurity -enable

answered Dec 13 '19 at 13:01

Waris Shams

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score 1 · Answer 22 · answered Jan 28 '20 at 22:18

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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.

answered Jan 28 '20 at 22:18

Stephen J

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Xcode 9: Could not attach to pid

22 Answers22

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