xcode 15 Beta 5 iOS Simulators... Springboard Crash & High CPU

Recently I have very bad experience with simulators. I can't run them at all, almost immediately crash upon launching. Preview in Xcode works occasionally. I tried today to reinstall macOS, Xcode, (I erased my HDD before that). I started a fresh new project in Xcode and I can't run it on the simulator, it crashes instantly.

What I noticed from the logs is that:

Sep 27 22:07:14 Vasils-MacBook-Pro CoreSimulatorService[810] <Notice>: com.apple.CoreSimulator.CoreSimulatorService 920.6 starting.

Sep 27 22:07:23 Vasils-MacBook-Pro CoreSimulatorService[810] <Error>: Unable to load device.plist: /Users/bacata.borisov/Library/Developer/CoreSimulator/Devices/DC8880C0-5D67-4DAA-95B6-75043F690485/device.plist Sep 27 22:07:23 Vasils-MacBook-Pro CoreSimulatorService[810] <Error>: Failed to create device at path /Users/bacata.borisov/Library/Developer/CoreSimulator/Devices/DC8880C0-5D67-4DAA-95B6-75043F690485. Sep 27 22:07:23 Vasils-MacBook-Pro CoreSimulatorService[810] <Notice>: Device iPhone 12 Pro Max (1319CD25-F09C-4BC4-8E8C-E1A7D810BDC0, iOS 17.0, Booted) encountered in unexpected state at launch: Booted. Shutting down. Sep 27 22:07:23 Vasils-MacBook-Pro com.apple.Console[808] <Warning>: Unable to discover any Simulator runtimes. Developer Directory is /Applications/Xcode.app/Contents/Developer. Sep 27 22:07:23 Vasils-MacBook-Pro CoreSimulatorService[810] <Warning>: Found duplicate SDKs for appletvos17.0:

Basically it doesn't see the runtime even though it is installed. Has anybody else experienced that? I am going a little bit crazy already I don't know where exactly the runtime is supposed to be, do you have any suggestions?

In general, the only way to ensure that Xcode releases get fixed is to email Craig Federighi (head of software) or Ken Orr (head of developer tools) directly.

Filing “feedback” or discussing the problem on these forums will have no effect—unless you catch Eskimo’s attention and he runs the issue up the chain on your behalf.

I would encourage you all to email those executives. If they see enough noise, someone will force engineering to take a look. Otherwise, this issue will run for a year because Apple‘s feedback process is absolutely broken.

I've also seen this problem since the early Xcode 15 betas and I never understood why and when it happened. Today I've been investigating more in depth, trying to reproduce the problem.

The problem

After starting an iPhone simulator using iOS 17 (either by running an app or by triggering SwiftUI Previews), CPU consumption goes very high and does not come back to "background level" even after many minutes of wait. Beside the SpringBoard process we can see the following 5 other processes with high CPU consumption:

• PhotosPosterProvider
• ExtragalacticPoster
• CollectionsPoster
• two instances of diagnosticd (background processes which are consuming the logs generated by the processes?)

My current setup

Xcode Version 15.0 (15A240d) Simulator running iPhone 14 using iOS 17.0 (21A328)

Reproducible steps

Version 1: simulator using iOS 17

1. Create a new iPhone simulator using iOS 17.
2. Start it up (either from "Simulator") or by running an app.
3. Wait and see... You will see that most of the processes consuming a lot of CPU, will come down after a few minutes. But SpringBoard will stay up.

Version 2: Switching languages

1. Start "Settings" app, go to "Language & Region" and add/switch to another Language, for example to "German".
2. Poster processes will get restarted and SpringBoard will automatically start logging messages again.

Version 3: "The real cause"

Until now we have never tried to understand what those "Poster" processes are. The following steps will indicate clearly where the bug lies:

1. With the Simulator running (with no CPU hog running) lock the iPhone by pressing CMD+L (or the side-button in the UI).
2. Wake up the iPhone by touching the screen or tapping CMD.
3. Tap and hold the screen to go to the FrontBoard configuration screen.
4. Swipe to the left and select "Add new". The "Add New Wallpaper" screen will appear, starting to populate the prepared examples to select from.

==> SpringBoard will again start to log

Workaround

I use the following workaround to remediate. In the end, it is always about killing the Poster processes.

Variant 1: The annoying restart

Restart the device and hope for the best... If after a few minutes the high CPU persists, restart the device again.

Variant 2: targeted kill of the problematic processes

Use "Activity Monitor" to kill the "Poster" processes which consume CPU. Search for "Poster" check CPU consumption and stop the process.

Use the following shell command to kill all processes being part of "CoreSimulator" and having "Poster" in the name.

ps aux | grep -E '[C]oreSimulator.+Poster' | sort -r -k3 | awk '{if ($3>0.0) { print $2}}' | xargs kill -1

The only thing that brings things to normal for me is to quit the simulator app and Xcode. Then relaunch. Still getting it with Xcode 15.0.1. I don't really see the Poster process, just SpringBoard and diagnosed

In first time boot it'll take that much processor later work Fine : MacBook Air M1

For me, on my M1 Mac Mini, it was fixed by changing File > GPU Selection > Prefer Discrete GPU. Automatic / Integrated GPU didn't change much and springboard was consuming 40% of CPU per each simulator.

XCODE 15.4 using iOS 17.2 caused this for me for months and months. Now hopping to 17.4 seems to have fixed it. So many endless error loops before. This is better.