I have upgraded macOS Sierra Developer Preview, but my Xcode 7.3.1 gives below error while try to run my project on simulator. In addition Generic to archieve gives another error like:
In addition for archive: a cryptographic verification failure has occured.
How can I fix this?
I have tried before Xcode 8.0 Beta, uninstall it deleting derivedData and reset content simulator but still occurs this error.
Update:
I want to share an information who want to use Sierra now. If you decide to do below changes you need to know "Uploading App Store with beta software" not allowed by Apple. Continue with El Capitan and Xcode 7.3.1 for production.
If you want the slow solution, you can reinstall Xcode 7.3.1 by downloading it from https://developer.apple.com/download/more/.
It worked for me and now my Simulator is able to start again without getting the error.
The issue is discussed in depth here:
How to fix Xcode "DTAssetProviderService could not start.." error?
This seems to be a major bug. Until Apple fixes it, you can work around it:
Build app
The app will still install on the simulator, even with the error
Launch the app manually on the simulator
Go to Xcode
Click Debug > Attach to Process > Your App Name
That will enable Xcode debugging features and allow your app to run in simulator. Definitely not ideal, but hopefully you can use this until a real solution comes out.
This is a regression in macOS Sierra that multiple developers have reported in the forums and in the lab sessions at WWDC. Xcode 7.3 is not supported on Sierra. If you want to use macOS Sierra, please use Xcode 8.0 beta or later.
If you must use Xcode 7.3 on Sierra, you can partially workaround this bug by using Xcode.app to install the app through Build & Run, launch the app suspended from the command line (xcrun simctl launch -w booted <app identifier>) and then attach with the debugger and resume the suspended process.
Note that this issue only impact Xcode 7.3.1 downloaded from the Mac App Store. You will not hit this issue if you use Xcode downloaded from http://developer.apple.com (ie, the "drag & drop installer"). Note that you might hit another issue with the same symptoms when using the drag & drop installer. That is discussed in DTAssetProviderService could not start DTXConnection with Simulator
You can still run the debugger, but you have to attach it manually.
You can run your app tapping the icon in the simulator, than switch back to Xcode and select Debug, Attach to Process and pick your app process.
The following steps fixed the issue for me:
Remove both Xcode 7.3.1 and 8 Beta
Remove /Library/Developer and ~/Library/Developer (before removing check the contents and back up whatever you need)
Download the Xcode 7.3.1 DMG file and the Xcode 8 Beta xip file (unless you already have them)
Install 7.3.1 and test the Simulator (should work fine now)
Install 8 Beta and test the Simulator in 7.3.1 again (should work as before)
Restore what you backed up on step 2
Related
I'm running the latest version of macOS Big Sur with Xcode 12.2 beta 3. I build my app for the simulator and it succeeds - but the simulator screen is blank. The same thing happens when I go through the menus and open Simulator manually - Xcode > Open Developer Tool > Simulator. I have tried adding a new simulator device, and running xcode-select --install.
Preferably, I would rather not have to re-install Xcode as I have limited space and would have to juggle other applications, use an external hard drive etc (I have a 128GB MacBook Air).
This is what appears when I try both methods.
I determined the problem.
There was a bug in the developer beta version I was using.
It was causing the simulator to fail to launch correctly.
I have reported this bug to Apple through Feedback Assistant, and moved to a stable version of Xcode which is now working with the simulator.
I agonised over this for ages since I moved to the MacPro M1.
App run fine on connected fysical IOS device but not in emulator...
Upgrading MacOs and Xcode fixed nothing...
Was finally on MacOS 12.3.1 and Xcode13.3.1 when I figured it out.
The only thing that finally actually worked was removing the check to run Xcode with Rosetta and to be sure downloading a new IOSXXX simulator.
Go to Applications -> right click on Xcode --> Get info --> uncheck Open using Rosetta.
Hope it helps for you!
I know that so many people have asked this question earlier. But I think my situation is different. In my case Xcode 9.2 was already installed and I upgraded macOS from 10.13.2 to 10.13.5. Then I installed Xcode 10 beta. Now when I'm running any project on Xcode 9.2 and try to use simulator, its becoming black though I can see the xcode logs. Things I have tried so far,
Uninstalled Xcode 10 Beta
Uninstalling & reinstalling Xcode 9.2
Uninstall Xcode 9.2 and install Xcode 9.4
Reset Content & Settings from simulator menu
Restart Device from simulator menu
Resizing simulator.
Followed this post and cleaned DerivedData, CoreSimulator, iOSDeviceSupport
Re add simulators from devices & simulators section
Now what should I do now?
Try running defaults write com.apple.CoreSimulator.IndigoFramebufferServices FramebufferRendererHint 3 in Terminal (source). Note that this will force Simulator to use OpenGL instead of Metal, so you'll want to re-run it with 0 once this gets fixed.
try workaround, delete Library/Developer folder and start it again
Another option that occurred for me. I subclassed UIWindow and called .init(frame: .zero). Changing to .init(frame: UIScreen.main.bounds) fixed it.
Open up XCode 9 and go to add additional simulators(pictured below) re-add iOS 10 and iOS 11 simulators
You seem to have tried everything except changing the iOS simulator version you are trying to run.
Maybe the problem lies with that specific version of iOS simulator eg. iOS 11.x iPhone 6. Change that and it may run OK.
If you do not have desired version with you, go to XCode->Preferences->Components, and download one of the older iOS simulators available at the time of XCode 9.x.
Then, go to XCode->Windows->Devices and Simulators. Press + sign at the bottom left of the screen. Add your desired simulator version (give your desired name), so that this newer simulator appears in runnable scheme list of XCode.
This is just for the users that failed trying everything to save Xcode 10 and then reinstalled Xcode 9.4.1 and the simulator still not working.
Here is what I did to give Xcode 9.4.1 back running.
After I got this problem after upgraded to Xcode 10.
I tried that famous FramebufferRendererHint, didn't work for me.
I have found out the Xcode 10.1 beta release didn't fix the problem for someone else, so I didn't bother to try 10.1 beta.
From the online research I know the problem is in /Library/Developer/PrivateFrameworks/CoreSimulator.framework.
Without Xcode even installed on your Mac /Library/Developer doesn't exist.
So it is installed by Xcode when your first time run Xcode. You would notice a screen showing "Installing Components"
But after you installed Xcode 10 and then install/run Xcode 9.4.1 it won't touch that folder anymore. So problem stays even you put Xcode 9.4.1 back
That's why after I downloaded Xcode 9.4.1 expanded and ran it. Problem still there.
I didn't backup my Mac. So I decided to start from scratch. Restored my MacBook from Internet, downloaded Xcode 9.4.1 again. and now everything is back to normal.
I can keep releasing the App to App Store now.
In my case (xcode 10), I just left the computer for 10 minutes or so (out of frustration!) and when I came back I found it at the starting screen! .... I guess for the first time it takes time
Problem: I cannot simulate an Apple watch interface. Whenever I try and test my Apple watch app on the iPhone 6 simulator, Xcode successfully finishes and builds the app, attempts at opening simulator and fails with an error message which reads 'Invalid Device State'.
I believe simulator has a watch simulator that opens along with the compatible iPhone simulator models that can communicate with Apple watch (example: iPhone 6) Although I have yet to see it work. I have built a universal interface for iPad and iPhone and another for the watch, so it's not a matter of the app being for the wrong device. Whenever I test on my actual iPhone I can test the universal interface successfully.
I'm using Xcode 6.2 on iMac OS X 10.10.3
I have tried restarting Xcode/Computer. I can't seem to find any other mention of 'Invalid Device State' anywhere, hopefully due to it being an obvious thing to avoid/fix that I've overlooked. Any help would be appreciated.
Force Quit xCode and restart will resolve problem.
I had come across this issue after updating Xcode 6.4 to 7.1.
Below are fixes for this :
Clean project (cmd+shift+k) as well as clean build folder
(cmd+shift+k+option)
Quit simulator and run again
Quit Xcode and Simulator and run again
Restart your Mac.
Solution 3 worked for me!
I had the same issue. Generally it is because you just update Xcode or change its name in the Applications folder.
If you just restart your computer it will work correctly.
Hope it helps !
I observed this happening when more than one Xcode app installed.
To fix this,
Launch Xcode and click preference..,
Go to "Location" Tab, Select correct options from "Command Line Tools" dropdown
Quit Xcode and relaunch it.
Run your app.
First of all, just clean the project.
Quit your project.
Quit your Xcode.
Restart Xcode.
This happens to me when I have two different Xcode versions running at the same time. Hopefully this helps you.
No need to quit, restart or even re-install. Switch to another iOS Simulator device (6s if you were using 6s plus) and voila!
Nothing worked for me on XCode 7.3.1.
Had to reinstall it to make the simulator work.
Go to applications folder. Drag drop XCode to Dustbin.
Empty dustbin contents.
Go to App Store and install XCode.
Run XCode. The simulator should work now.
I have Xcode 7.3 and Xcode 8.0 Installed.
If a am working with Xcode7.3 and opens Xcode8.0 to get some code from Xcode8.0 project.
When i run my application on Xcode7.3 So it will give me same error.
Solution is simple ForceQuit or Quit all Xcode's and open the required one.
In my case, the simulator would show an indefinite black screen whether attempting to run a project, or running the simulator directly (which should bring you to the simulated home screen). This would happen even on a newly created simulated device.
After the existing suggestions failed, the following worked for me:
Delete the Simulator
Delete XCode
Delete the Developer folder
Reinstall XCode from the app store. This requires attempting to run XCode again so that Mac OS will realize it's no longer installed.
Jus clean the project and restart Xcode. This happens to me when I have two diffent xcode versions running at the same time.
Robust fix is Just Quit your xcode and run again, hope so it will help you. This heck work for me.
On M1 Mac I've found more than 3 open simulators can cause this error. Quit the simulator app to fix this error.
I am pretty sure that in my case the simulator was corrupt after a failed language change.
Following this answer to reset the simulator worked.
I cannot launch the simulator successfully. Once I launch the IOS Simulator this error appears:
"Unable to boot the IOS Simulator."
Following the IOS Simulator error, I then get an error from Xcode reading:
Unable to run app in Simulator
An error was encountered while running (Domain = DTiPhoneSimulatorErrorDomain, Code = 2)
UPDATE:
This might sound silly but I went to Xcode/preference/Downloads with intentions of seeing a IOS 8.0 Simulator but there was none. Could this be the problem? Am I suppose to have a IOS 8.0 Simulator? If so can someone direct me how to get it? Also, under the "Downloads" tab in Xcode preference I do see IOS 7.0 and 7.1 Simulators and both work fine with Xcode 5.
the trick is, to select the right command line tools!
just select it here
reboot(!) and everything is fine again :-)
Ok It's known problem. Do you see simulators list? If not
Goto Xcode Menu -> Open Developer Tool -> It will open a simulator in your Dock -> click on simulator then go to Simulator Menu: Hardware -> Device -> Manage Devices. Add needed simulators. Always try to run your app with different simulators.someone will work.
Restart your Mac. I just had that exact error after installing Xcode 6 beta 7, literally the only thing I did in response was reboot my Mac and now the iOS 8 simulator is working.
This error is common if you update Xcode without restarting afterwards.
In my case, i reset ios simulator settings fix it.
iOS Simulator -> Reset Content and Settings ...
Open Xcode 6 beta
Goto Window > Devices
Click on the little + sign at the bottom
Add (if missing) all the devices that you want, or delete and recreate if not working.
If anyone of the simulator is not working then you can delete it and then re-create it again in this menu.
I saw the same issue when I installed Xcode 6 beta 6, and deleted beta 4 and beta 5. Apparently, deleting the old betas also deleted the iOS Simulator 8 versions! Putting it back from my Trash solved the issue.
Solution: Don't delete old beta software!
Edit: #Flori's solution worked. Was able to delete the old beta software, and after a complete system reboot, it worked again.
From the xCode 6 pull down menus, Xcode > Open Developer Tool >
iOS Simulator (if you get a pop up error just dismiss it)
Once in the Simulator go to Hardware > Device > Manage Devices.
Delete everything listed under simulator.
Reboot your machine.
After that, navigate back to Manage Devices in the simulator and click the plus to add back your simulators. Then the iOS 8 simulators will show up.
Just unset DYLD_INSERT_LIBRARIES environment variable in the /etc/launchd.conf or ~/.launchd.conf file. Which you can edit by sudo vi /etc/launchd.conf command. remove the above flag save it by "ZZ" (captial Z) and reboot the system. It works like a charm.
Make sure that path in menu XCode>Preference>Locations point to XCode 6.0 (Restart Xcode after changing them). Then go to menu Window>Devices and add simulator devices you want to use.
Edit: Turns out I was getting my version of the error because I had a file (the "Empty File" type) named "Frameworks" in several of my projects, and this was causing big issues with the iOS 8 simulators. Renaming the file to be anything else, and then doing a Clean Build Folder fixed it right away.
------Deprecated Original Message Below--------
In case this helps anyone -- I was having a similar error on Xcode 6 GM, and tried everything mentioned in these Answers, but the iOS 8 simulators would never run any of my apps (no problems with iOS 7 running from Xcode 6 though).
What did sort of work was creating a new project (new project apps would run in the iOS 8 simulators, but never any luck with existing apps). Copying over files and project settings is no fun, but at least it let me do testing and see if my apps needed fixing for the iOS 8 public release.
Extended description of problem at https://devforums.apple.com/thread/246751
I tried everything mentioned above and nothing worked.
Finally the only way to make it work was unsetting DYLD_INSERT_LIBRARIES=/usr/lib/libimckit.dylib
How I did this:
Open terminal and typing "sudo vi /etc/launchd.conf"
Changing
"setenv DYLD_INSERT_LIBRARIES /usr/lib/libimckit.dylib"
to
"unsetenv DYLD_INSERT_LIBRARIES /usr/lib/libimckit.dylib"
Save changes
Reboot your system
In this post [1] explain what DYLD_INSERT_LIBRARIES is for
[1] https://stackoverflow.com/a/26053165/2091181
I got this issue when moving from Beta 6 to Beta 7. Very frustrating. I could reset content and settings on any of the iOS 8 simulators. None of my iOS 8 simulators were working at all, just a black screen. I restarted my machine during the process, but I am not sure if it did anything. Initially I had only iOS 8 Simulators. I had to remove and reinstall Xcode6Beta7. I did not get the Install More Components the first time I installed it, I am not sure if that was the missing part. I installed the iOS 7 Simulators from Settings->Downloads because my iOS8 ones were not working. After I had reinstalled and relaunched the simulator, I then had a list of iOS 6,7,& 8 simulators. None of the iOS 8 Simulators were working. I was able to launch the iOS7 simulator and then using the device menu change to an iOS 8 Simulator. Some still did not work, I had to remove them and re-add them in the devices screen.
Remove XCode6Beta from Applications.
Restart Machine (Just in case, this seems to solve some peoples issue completely)
Install XCode6Beta.
Verify the Install Additional Components ran.
Launch Xcode6Beta.
Preferences->General->Change Command Line Tools to Xcode 6.0.
Restart Xcode.
Preferences->Downloads->Download iOS 7 Simulator (If not already downloaded).
Run App on iOS 7 Simulator (Or launch iOS Simulator and switch to iOS 7 device)
If the iOS 7 Simulator is working, Hardware->Devices->Select an iOS 8 simulator.
Delete and recreate any non working iOS 8 Simulators in Window->Devices from Xcode.
I wrestled with this for a bit, with the simulator app reporting that it couldn't find the iOS8 simulator, and suggesting updating in Prefs/Downloads, which didn't work. I tried re-installing Beta 6 twice (without removing all the support files, which would have been next). The initial installation described itself as build 6A280c; a fresh download yielded build 6A280e. No luck.
Eventually, I opened Window -> Devices, and used the "+" button in the lower left to add a new simulator for iPhone 5s, iOS 8, naming it "Fresh 5s". The Schemes popup now displayed three iPhone 5S/iOS 8 options (none with the name I designated, but differentiated by UUIDs); at least one of them worked.
I'm guessing that this feature (collections of arbitrary simulator instances) will be very useful when it's baked. In the meantime, I guess I'll need to manage the list of simulators manually.
Do following steps worked for me:
1. Launch the iOS Simulator and go to iOS Simulator --> Reset Content and Settings...
2. Close all the applications and restart your mac
3. Open Xcode6.0.1 or 6.0 and test the iOS Simulator
Had the same problem after moving from Xcode 6 beta 5 to beta 6, but also for the iOS 7.1 simulator. Restarting my machine seemed to do the job. I did not need to update from Xcode 5.1.1 CLT to Xcode 6.0 CLT.
I tried all of the solutions above, and was still unable to launch the iOS8 Simulator. The iOS7 Simulators all launched fine.
Looking at the Console, I found that the launch was crashing, and the crash log complained about the dynamic library, libimckit.dylib. You can read about that here:
https://discussions.apple.com/thread/5781366?start=0&tstart=0
The quick solution, remove that and its partner library, reboot, and it loads.
Is there anything interesting in ~/Library/Logs/CoreSimulator/CoreSimulator.log?
The "Unable to boot the iOS Simulator." error message is almost always because launchd_crashed because DYLD_INSERT_LIBRARIES was set to something not compatible with the iOS Simulator runtime. Do you have any crash logs (eg: launchd_sim crashes) in ~/Library/Logs/DiagnosticReports? If so, check if they show DYLD_INSERT_LIBRARIES being set. If that's the case, your options are to either update to an OS X Yosemite host (which will deal with this issue) or unset DYLD_INSERT_LIBRARIES (likely set in /etc/launchd.conf or ~/.launchd.conf)
Force Quit All the apps including xcode and simulator
Restart MAC
Checking in the "Locations" Xcode preference, I had two items of the same version, one located in the app translocation area (/var/.../AppTranslocation/...). Also I had previously done a manual command line tools install. To resolve this in the end I had to delete /Applications/Xcode.app and remove the manual command line tools install:
sudo rm -rf /Library/Developer/CommandLineTools
Then installed Xcode anew, and rebooted. Boom! Simulator working again.
Reboot your mac os. its working correctly on xcode 11.3.x and mac os 10.14.6.
I cannot launch the simulator successfully. Once I launch the IOS Simulator this error appears:
"Unable to boot the IOS Simulator."
Following the IOS Simulator error, I then get an error from Xcode reading:
Unable to run app in Simulator
An error was encountered while running (Domain = DTiPhoneSimulatorErrorDomain, Code = 2)
UPDATE:
This might sound silly but I went to Xcode/preference/Downloads with intentions of seeing a IOS 8.0 Simulator but there was none. Could this be the problem? Am I suppose to have a IOS 8.0 Simulator? If so can someone direct me how to get it? Also, under the "Downloads" tab in Xcode preference I do see IOS 7.0 and 7.1 Simulators and both work fine with Xcode 5.
the trick is, to select the right command line tools!
just select it here
reboot(!) and everything is fine again :-)
Ok It's known problem. Do you see simulators list? If not
Goto Xcode Menu -> Open Developer Tool -> It will open a simulator in your Dock -> click on simulator then go to Simulator Menu: Hardware -> Device -> Manage Devices. Add needed simulators. Always try to run your app with different simulators.someone will work.
Restart your Mac. I just had that exact error after installing Xcode 6 beta 7, literally the only thing I did in response was reboot my Mac and now the iOS 8 simulator is working.
This error is common if you update Xcode without restarting afterwards.
In my case, i reset ios simulator settings fix it.
iOS Simulator -> Reset Content and Settings ...
Open Xcode 6 beta
Goto Window > Devices
Click on the little + sign at the bottom
Add (if missing) all the devices that you want, or delete and recreate if not working.
If anyone of the simulator is not working then you can delete it and then re-create it again in this menu.
I saw the same issue when I installed Xcode 6 beta 6, and deleted beta 4 and beta 5. Apparently, deleting the old betas also deleted the iOS Simulator 8 versions! Putting it back from my Trash solved the issue.
Solution: Don't delete old beta software!
Edit: #Flori's solution worked. Was able to delete the old beta software, and after a complete system reboot, it worked again.
From the xCode 6 pull down menus, Xcode > Open Developer Tool >
iOS Simulator (if you get a pop up error just dismiss it)
Once in the Simulator go to Hardware > Device > Manage Devices.
Delete everything listed under simulator.
Reboot your machine.
After that, navigate back to Manage Devices in the simulator and click the plus to add back your simulators. Then the iOS 8 simulators will show up.
Just unset DYLD_INSERT_LIBRARIES environment variable in the /etc/launchd.conf or ~/.launchd.conf file. Which you can edit by sudo vi /etc/launchd.conf command. remove the above flag save it by "ZZ" (captial Z) and reboot the system. It works like a charm.
Make sure that path in menu XCode>Preference>Locations point to XCode 6.0 (Restart Xcode after changing them). Then go to menu Window>Devices and add simulator devices you want to use.
Edit: Turns out I was getting my version of the error because I had a file (the "Empty File" type) named "Frameworks" in several of my projects, and this was causing big issues with the iOS 8 simulators. Renaming the file to be anything else, and then doing a Clean Build Folder fixed it right away.
------Deprecated Original Message Below--------
In case this helps anyone -- I was having a similar error on Xcode 6 GM, and tried everything mentioned in these Answers, but the iOS 8 simulators would never run any of my apps (no problems with iOS 7 running from Xcode 6 though).
What did sort of work was creating a new project (new project apps would run in the iOS 8 simulators, but never any luck with existing apps). Copying over files and project settings is no fun, but at least it let me do testing and see if my apps needed fixing for the iOS 8 public release.
Extended description of problem at https://devforums.apple.com/thread/246751
I tried everything mentioned above and nothing worked.
Finally the only way to make it work was unsetting DYLD_INSERT_LIBRARIES=/usr/lib/libimckit.dylib
How I did this:
Open terminal and typing "sudo vi /etc/launchd.conf"
Changing
"setenv DYLD_INSERT_LIBRARIES /usr/lib/libimckit.dylib"
to
"unsetenv DYLD_INSERT_LIBRARIES /usr/lib/libimckit.dylib"
Save changes
Reboot your system
In this post [1] explain what DYLD_INSERT_LIBRARIES is for
[1] https://stackoverflow.com/a/26053165/2091181
I got this issue when moving from Beta 6 to Beta 7. Very frustrating. I could reset content and settings on any of the iOS 8 simulators. None of my iOS 8 simulators were working at all, just a black screen. I restarted my machine during the process, but I am not sure if it did anything. Initially I had only iOS 8 Simulators. I had to remove and reinstall Xcode6Beta7. I did not get the Install More Components the first time I installed it, I am not sure if that was the missing part. I installed the iOS 7 Simulators from Settings->Downloads because my iOS8 ones were not working. After I had reinstalled and relaunched the simulator, I then had a list of iOS 6,7,& 8 simulators. None of the iOS 8 Simulators were working. I was able to launch the iOS7 simulator and then using the device menu change to an iOS 8 Simulator. Some still did not work, I had to remove them and re-add them in the devices screen.
Remove XCode6Beta from Applications.
Restart Machine (Just in case, this seems to solve some peoples issue completely)
Install XCode6Beta.
Verify the Install Additional Components ran.
Launch Xcode6Beta.
Preferences->General->Change Command Line Tools to Xcode 6.0.
Restart Xcode.
Preferences->Downloads->Download iOS 7 Simulator (If not already downloaded).
Run App on iOS 7 Simulator (Or launch iOS Simulator and switch to iOS 7 device)
If the iOS 7 Simulator is working, Hardware->Devices->Select an iOS 8 simulator.
Delete and recreate any non working iOS 8 Simulators in Window->Devices from Xcode.
I wrestled with this for a bit, with the simulator app reporting that it couldn't find the iOS8 simulator, and suggesting updating in Prefs/Downloads, which didn't work. I tried re-installing Beta 6 twice (without removing all the support files, which would have been next). The initial installation described itself as build 6A280c; a fresh download yielded build 6A280e. No luck.
Eventually, I opened Window -> Devices, and used the "+" button in the lower left to add a new simulator for iPhone 5s, iOS 8, naming it "Fresh 5s". The Schemes popup now displayed three iPhone 5S/iOS 8 options (none with the name I designated, but differentiated by UUIDs); at least one of them worked.
I'm guessing that this feature (collections of arbitrary simulator instances) will be very useful when it's baked. In the meantime, I guess I'll need to manage the list of simulators manually.
Do following steps worked for me:
1. Launch the iOS Simulator and go to iOS Simulator --> Reset Content and Settings...
2. Close all the applications and restart your mac
3. Open Xcode6.0.1 or 6.0 and test the iOS Simulator
Had the same problem after moving from Xcode 6 beta 5 to beta 6, but also for the iOS 7.1 simulator. Restarting my machine seemed to do the job. I did not need to update from Xcode 5.1.1 CLT to Xcode 6.0 CLT.
I tried all of the solutions above, and was still unable to launch the iOS8 Simulator. The iOS7 Simulators all launched fine.
Looking at the Console, I found that the launch was crashing, and the crash log complained about the dynamic library, libimckit.dylib. You can read about that here:
https://discussions.apple.com/thread/5781366?start=0&tstart=0
The quick solution, remove that and its partner library, reboot, and it loads.
Is there anything interesting in ~/Library/Logs/CoreSimulator/CoreSimulator.log?
The "Unable to boot the iOS Simulator." error message is almost always because launchd_crashed because DYLD_INSERT_LIBRARIES was set to something not compatible with the iOS Simulator runtime. Do you have any crash logs (eg: launchd_sim crashes) in ~/Library/Logs/DiagnosticReports? If so, check if they show DYLD_INSERT_LIBRARIES being set. If that's the case, your options are to either update to an OS X Yosemite host (which will deal with this issue) or unset DYLD_INSERT_LIBRARIES (likely set in /etc/launchd.conf or ~/.launchd.conf)
Force Quit All the apps including xcode and simulator
Restart MAC
Checking in the "Locations" Xcode preference, I had two items of the same version, one located in the app translocation area (/var/.../AppTranslocation/...). Also I had previously done a manual command line tools install. To resolve this in the end I had to delete /Applications/Xcode.app and remove the manual command line tools install:
sudo rm -rf /Library/Developer/CommandLineTools
Then installed Xcode anew, and rebooted. Boom! Simulator working again.
Reboot your mac os. its working correctly on xcode 11.3.x and mac os 10.14.6.