No matching device (UUID) in set at /Users/<username>/Library/Developer/XCTestDevices - ios

I've been getting this error in Xcode 10.1 when running unit tests. It happens quite often.
When running unit tests in Xcode, test might pass or fail a few times. Then, after a few runs, this error appears, with Xcode not being able to launch or communicate with the iOS simulator.
Selecting a different simulator from the list is a workaround, but it gets a bit annoying having to do so. Furthermore, after a few unit test runs in the new selected simulator, the error comes back (with a different UUID).
Closing the simulator app and running the tests again does not solve the issue (same error alert appears). Neither does closing and reopening the project.
One thing noticed is, when Xcode gets in this state, closing Xcode (quitting the application) takes longer than usual. Closing Xcode and relaunching it, then running unit tests, also does fix the issue.

Window -> Devices & Simulators
Delete simulator
Add same simulator
Run tests again

Related

xCode 6 (beta 4) keep getting "The Simulator can't be launched because it is already in use."

I keep getting the "The Simulator can't be launched because it is already in use." when trying to run my app, this only happens about 20% of the time but once so far the only way to get around it is to restart my Mac.
Tried the following but doesn't help:
Cleaning my build folder
Closing and re-opening xCode
Force close of simulator
I'm Using xCode 6 (beta 4)
Any Ideas for a solution that doesn't entail me restarting my Mac?
Thanks
"The Simulator can't be launched because it is already in use.”
This messege will be shown only if there is another xcode project that has launched simulator and hasnt stopped it yet, and u try to run the simulator from another xcode project.
Ideally stopping the simulator from the respective project(PS. not closing the application from the simulator, clicking the STOP button) would do it,
But if it still is working like that, then Closing the simulator, or resetting the simulator contents.
If that still dsnt work, then as a last resort i would ask u to reinstall Xcode, as if this problem keeps going on, then ur downloaded file might be buggy.
P.S if u opt to re-download n install xcode please keep backup.
Hope it solves it. Although i want your problem to be solved by step 2.
This normally just happens when running an app (project) on the simulator and then trying to run another app while the simulator is open (and normally is still within the first app you launched and it can't quit automatically). As long as you keep running the same app you shouldn't get this error and as soon as you run another app just make sure you've closed the simulator before or at least left the previous app with the home button.
Just Restart Your Mac , It Will Fixed
I had the same problem and fixed it without restarting. You just need to reset the content on ios simulator, exit xcode, and then to make sure that you've completely exited, right clicking on the xcode icon on your mac nav bar and click Quit. Open it back up and it should work.

Xcode6 can't run any app in simulator ( Domain = NSPOSIXErrorDomain, Code = 3 )

No app can run in my simulator, although building is good.
Error messsage is below:
Unable to run app in Simulator
An error was encountered while running (Domain = NSPOSIXErrorDomain, Code = 3)
In my case, I tried to run the app on a iPhone 6 simulator when I got this error. Quitted the simulator only and re-ran the app on iPhone 5s (8.1) - it worked fine.
After a while I changed the target back to iPhone 6 (without quitting it), and ran the app against it - no error shown.
As mentioned in the Xcode 6.1 Release Notes and in my sticky post in the Apple Developer Forums for the iOS Simulator, this is a known bug in iOS.
Upon installation of an app, SpringBoard will SIGKILL that app's
process in order to force a relaunch of the app with the new
executable. The problem is that there is a race condition whereby
SpringBoard may accidentally SIGKILL a new process that we just
launched rather than the old process. Which of the various error
messages you get depends on exactly when in the launch process the
SIGKILL was delivered. Normally, this shouldn't happen, so the advise
is to just try again (sorry =/). If you find that this happes to you
all the time or more frequently than you can tollerate, we are
incredibly sorry. We are aware that systems with slower disk I/O will
see this happen more frequently than faster systems, so if you are
using an NFS home directory, you may want to create a local directory
for your simulator data and setup a simlink to it from
~/Library/Developer/CoreSimulator
By Quitting the Simulator and Run the application worked for me.
For me , just Reset Content and setting in your simulator
Restart Mac can solve the problem for me.
This error is less severe than "Domain = DTiPhoneSimulatorErrorDomain, Code = 2" error that I had when I switched to Xcode 6.
For this one, I just reset and cleared contents on my Simulator...quit. Rebuilt and ran my app...and it works.
Every time this has happened to me (as of this writing, still happening on Xcode 6.1) I do not need to restart my mac to fix it. Instead I only had to restart the simulator. I exit the simulator by right-clicking on its icon in the tray and selecting the option to Quit. The I re-run my app and the simulator starts from scratch and runs my app with no error. Much quicker than re-starting the mac.
Well, I had the same error popping up, but since I force quitted the simulator then ran the project again I got it fixed and running fine. Hope that helps you :)
If this error occurs with ionic framework, make sure you have an app id given in your config.xml
This is a generic error which says that it is unable to launch the app. The real error is in the log file. Go to the Simulator menu, Debug / Open System Log. Then press Reveal button to open the folder with actual Simulator logs. In my case it was CoreSimulator.log.
Here you will find the real error. My error was Could not register service com.apple.gputools.agent.producer.sim .
After a lot to struggle and trying all suggestions for half a day, I just went to simulator menu and chose File / GPU Selection / Use External GPU when available. That's it.
please download new xcode_6 beta 4. your project will work in simulator. As i have tested as well.
Sometimes the beta version of XCode is wrongly configured to use the command line tools from the previous xcode version.
This solution should fix the issue for you : https://stackoverflow.com/a/25415781/512504

Running app crashes iPhone5S and forces hard reset with the error "failed to get task for process" on the second launch only

I have been at this for hours and am about to start flipping tables. This problem cropped up out of nowhere after working on this app successfully for about a month. No changes to build settings or build schemes or anything that I can think of.
If I build and run the app on an iPhone 4 I have no problems at all. If I build and run the app on an iPhone5S it will:
On the first attempt: Build successfully, appear to install the app on the device and launch it, but then fail with "error: failed to launch '.../MyApp.app' -- NotFound".
On the second attempt: Build, run, have a happy little debug session and everything is perfectly fine and dandy.
On the third attempt: Build successfully, begin to launch the app, and then will fail with "error: failed to launch '.../MyApp.app' -- Failed to get task for process -1". The phone will then become unresponsive, and the only way to bring it back is a hard reset.
Once or twice throughout the past few weeks I've had this problem happen, but after resetting everything was fine. Turning on or off building for arm64 doesn't seem to make a difference, and I can't think of anything else that would be different between the two devices.
Even a hint would be appreciated.
UPDATE: I changed the build scheme to "Wait for app to be launched manually", and by launching it myself after it's been built it seems to avoid the crashing. Obviously this doesn't fix whatever the underlying problem is, but at least I can function now.
Looks like this is a known bug, and it's resolved in Xcode 5.0.2.
I'm experiencing this very same issue but the workaround I've found is to disconnect and reconnect the phone before running the app. Using this workaround, I haven't experienced the error as frequently as otherwise, but it's still a rather tedious process...
This problem is known back to first Xcode 5 Previews. It helps to disconnect and connect the phone again. MY worst experience was Preview 4 with iPad. It till happens occasionally, but very rare compared to before.

Unable to run app on iPhone simulator suddenly

My app has been running fine on iPhone simulator. I have hit an issue (discussed here: Intermittent error accessing core data model / contacts database) and now all of a sudden, it won't build and run on iPhone simulator. I have the following error:
Couldn't register com.yourcompany.XXX with the bootstrap server. Error: unknown error code.
This generally means that another instance of this process was already running or is hung in the debugger.(lldb)
Any thoughts? I have tried totally closing and resetting iPS as well as deleting the app and reinstalling but to no avail.
Very frustrating!!!
Reset your iphone simulator and clean up your xcode project.
Type
apple-alt-shift-k
in xcode.
It happens quite a lot for me, especially during frequent restarts of the simulated app. I tracked it down to (at least sometimes) a race condition or deadlock when the simulated app is shutting down and a new one is starting up.
Quitting the simulator usually work
If that does not help, restart Xcode
Sometimes processes may linger and restarting the Mac is ususally the quickest way to recover (although clever use of the killall command can salvage the situation if it is really inconvenient to restart).
Quit the iPhone simulator and run it again.
Quit the simulator and xcode.Also delete the app from your simulator.... and if it does not work goto target setting and change something like name of app in bundle identifier . and it should work
You are using Core Data. So its possible you changed the dataModel and NSManagedObject class is changed. So it will crash until you delete application from simulator and run your project again..

Why does my app work in the simulator but get stuck on the splash screen when I run it on my iPhone?

My app runs fine on the simulator. However, when I run it on my iPhone, it gets as far as displaying the splash screen and then just stays there. It's an iPhone 3GS and the software version is 5.0.1. That's what happens when Debugger = None. When Debugger = GDB, I get an error message, 'Thread 1: Program received signal: "SIGABRT"', which I have learned can mean almost anything. I'm running Xcode 4.2.1.
I'm coming off a long hard night of battling with this error message, which appeared seemingly out of nowhere in a stable mature app. I tried to roll back with time machine, I deleted the Derived data for my project in Organizer a few times and did some of the other stuff recommended in this thread.
XCode 4 hangs at "Attaching to (app name)"
It got ugly. For a while, I couldn't even reboot my machine. Eventually, I was able to relaunch finder and suddenly the Simulator was working again. Two more pieces of information, I used to have to click allow in two dialog boxes when running on my phone but now it's only one (the one about code signing, I forget what the other one was about). Second, I find all the build architecture target stuff confusing but I set all my Base SDKs to be latest iOS. Lastly, I tried Product --> Clean and then Build but that didn't fix it. As you may have gathered, I'm getting my butt kicked. Any help would be much appreciated.
Dessie
Many times I have experienced Xcode going "crazy" with a physical device connected. At times I saw the behavior you describes; other the app simply refused to start;
In all of those cases, I could fixed it in either of two ways:
disconnect the iphone and connect it again;
reboot the device.
This is a very common problem that is easily fixable.
1) remove the app from the device
2) reboot the device
3) close Xcode and you must restart, logging out will not work

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