Unable to Launch Tests/UITests in Xcode 16 with iOS 18 Simulator

Question

Gong OP

Created Aug ’24

Replies 11

Boosts 6

Views 3.1k

Participants 9

Hello,

I'm unable to run any test cases in Xcode 16 with the iOS 18 simulator.

Steps to Reproduce:

Create a new iOS project in Xcode 16 using the default iOS app template with the testing option checked.
Run any test or UI test case by clicking the "Play" icon in the Test navigator.
Xcode gets stuck at the "Testing" state indefinitely.

Environment:

macOS 15 beta 8
Xcode 16 beta 6
iOS 18 beta 7 simulator

Answered by Gong in 856495022

RESOLVED:

I used Realm database.

After the app creates any FIFO file, the simulator can no longer be cloned. An error occurs during the simulator data copy process, indicating a lack of permission to copy FIFO files.

This cloning failure prevents Xcode from launching tests properly. A simple way to reproduce this issue is to create a new iOS app, add a Realm database, and create any database file (since Realm creates FIFO files for interprocess communication). After that, the simulator can no longer be cloned.

To work around this issue, I wrote a script that removes all pipe files from the simulator directory.

Boost

Answer 1

Gong OP

Sep ’24

Accepted Answer

xcrun simctl delete all

This resolved the issue. However, you need to manually add all the simulators after this.

0

Answer 2

Developer Tools Engineer OP

Apple

Sep ’24

I would suggest not deleting simulator devices to workaround this issue. If there is something bad about the device state, I'd prefer to triage that to figure out what is going wrong. Could you collect a sysdiagnose and simctl diagnose when in this state and file a feedback report?

1

Answer 3

Gong OP

Sep ’24

@Developer Tools Engineer FB15244277

0

Answer 4

Phoebe15 OP

Oct ’24

Hello, I have exactly the same issue. Xcode 16, macOS sequoia 15.0.1, simulator iOS 18.

Do you have a suggested solution?

1

Answer 5

JessicaDev OP

Oct ’24

I am having the same issue with Xcode 16. Tests would run in any device with iOS 17 but not in any device with iOS 18.

I ran: xcrun simctl delete all and manually installed two simulators, one with iOS 17.0 and one with iOS 18.0. At first neither would work and was stuck on testing... but after restarting my computer the iOS 17 simulator works and the iOS 18 simulator still just says testing...

0

Answer 6

Phoebe15 OP

Oct ’24

xcrun simctl erase all solved the issue for me

1

Answer 7

JohnD OP

Nov ’24

I'm having this issue too but the solution didn't work for me.

0

Answer 8

HappYBoT OP

Dec ’24

Any news on this issue? Current solution written didn't worked for me :/

0

Answer 9

AliaksandrMazurau OP

Dec ’24

In my case, removing and redownloading the simulator did not help either. I discovered that the issue was caused by an outdated version of Dynatrace library. After some investigation, I found that such issues often occur when a new version of Xcode is released (this happened with Xcode 15 and earlier versions as well). I recommend checking your project dependencies to ensure they are up to date.

0

Answer 10

vincefried-rd OP

Feb ’25

Any news here? Deleting and readding simulators has become a recurring procedure for me. I need to do it at least a couple of times a week to fix this issue. It takes away time I can also spent developing features or doing other things.

0

Answer 11

Gong OP

1d

Recommended

RESOLVED:

I used Realm database.

After the app creates any FIFO file, the simulator can no longer be cloned. An error occurs during the simulator data copy process, indicating a lack of permission to copy FIFO files.

This cloning failure prevents Xcode from launching tests properly. A simple way to reproduce this issue is to create a new iOS app, add a Realm database, and create any database file (since Realm creates FIFO files for interprocess communication). After that, the simulator can no longer be cloned.

To work around this issue, I wrote a script that removes all pipe files from the simulator directory.

0