My development work is paused as Xcode is now non-functional on my Macs. Loading any project into Xcode soon leads to a hang and Force Quit. The SDKs are listed as "status unavailable". No Simulators are available.
I've tried previous versions of Xcode; removing everything and re-installing; installation from the Store and direct from the Apple Developer site.
I've created a Feedback issue.
This happens on both of my Mac minis.
I'm running Tahoe 26.4 (25E246) on both.
I've created a Feedback issue.
What's the FB number? If there isn't a sysdiagnose attached, please make sure to update your report with one so we have details on what's happening.
I filed a similar report yesterday...
Xcode 26.4 (17E192) Simulators Keep Showing As Unavailable After Successfully Intalling Them
FB22346008
... with sysdiagnose tarball and screen shots. Am also running Tahoe 26.4.
I spent the better part of this evening removing the following items:
/Applications/Xcode.app
/Library/Developer
~/Library/Developer
~/Caches/com.apple.dt.*
~/Preferences/com.apple.dt.*
/private/var/tmp/com.apple.CoreSimulator.SimDevice.*
rebooting my machine, and then reinstalling Xcode 26.4 (Apple Silicon) and the command line tools. I then used xcrun simctl to flush all of my devices and runtimes. I spent a lot of time fighting Xcode because after removing old simulators, Xcode automatically downloads them all again (SMH!). Once Xcode seemed to stabilize its downloads (using xcrun simctl list to monitor everything), I then added the iOS, watchOS, and tvOS simulators for 26.4. So far, things "seem" to be behaving. We'll see whether or not I wake up tomorrow to joy or despair.
I have a 2021 MacBook Pro (M1 Max) and have developed solidly on it ever since I got it. This is the first version of Xcode that has trainwrecked my world since the horrible days of Xcode 6. Ugh!
And today Xcode's simulators are all unavailable again!
I woke up my machine after it went to sleep overnight, and Xcode seemed happy and showed all the simulators. So then I decided to reboot the machine just to make sure, and now Xcode is showing everything as "Status unavailable" again, and all of the previously downloaded runtimes are gone. And xcrun simctl list just hangs, requiring a Ctrl-C to kill it.
To anyone from Apple who is listening ... stop cramming AI slop features into everything and focus on fixing the bugs! This is unacceptable.
I'm now wondering if this is a macOS 26.4 issue. I clean everything out again, reinstalled Xcode Xcode 26.3 (17C529), did the simulator updates (and waited for Xcode to stabilize its other downloads), rebooted, and all the simulators it had installed were in "status unavailable" state again.
How could anybody at Apple not have encountered this, and why was it released to the public?
Last post ... I promise ...
When I reinstalled Xcode 26.4 again after going through all of the above shenanigans, I chose to NOT install the 26.x line of simulators, nor the Predictive Code Completion Model. As before, Xcode downloaded and installed older simulators anyway, but left the 26.x options uninstalled with their "Get" buttons primed and ready. I closed down Xcode and did some other stuff. After an hour I launched Xcode to check on things, opened Settings and, lo and behold, the iOS 26.4 and watchOS 26.4 simulators were showing as installed under the Platform Support section of the Components.
What is going on? It's as if Xcode is hallucinating.
xcrun simctl list just hangs for me.
I found my Intel based Mac Pro still works with the same set-up. One of my Apple Silicon Mac minis sort of works, one does not no matter what I try.
Yes, when it's in the "bad" mode, xcrun simctl list will hang forever.
That's interesting that it still works on your Intel machine. I've been holding off upgrading my older Intel MBP to the 26.4 updates for fear that it would wreck that environment too.
I am seeing similar behavior using macOS 26.4
No clue how to fix this...
File a bug report. I think Apple's bug algorithms won't flag anything unless there are multiple reports on the same bug.
Although their Music app still can't properly handle gapless song lists reliably (e.g., Pink Floyd) and yet multiple people have been yelling about this over the years, so I may be off base as to how they prioritize their work. I don't think they have anyone to put the fear of God into them any more like Steve Jobs did when the engineers generated bad code.
I was seeing the same behavior using macOS 26.4. Now seeing it on 26.5 beta.
My iMac Pro running sequoia and the Intel version of Xcode is working fine.
Just chiming in to say I also am running into this. As my only machine is a 14" M1 Pro I am now out of luck in running Xcode at all for my projects
It suddenly started happening to me on Tahoe 26.4 running Xcode 26.4 on an M2 MacBook Air.
I submitted feedback: FB22384447
The latest Xcode Beta does not work either. Hangs almost immediately.
I ended up burning my Mac down to the metal and its working now…
+1, this gave me a hard time when prewarming Xcode on our dedicated CI machines.
Same symptoms, xcrun simctl unresponsive, Xcode showing unavailable status, hanged in overall.
I can't really recall this happening ever before. 🤨
I have the same issue with Xcode 26.4 after installing macOS 26.4.
What help is (do it at your own risk, no guarantee):
rm /Library/Developer/CoreSimulator/Images/images.plistYou will be able to download the Platform Support Components from Xcode again.
@diniska , does your remedy survive a reboot of the machine? When I tried my cleaning (I did the whole CoreSimulator directory, but now I see that I probably only needed to do the images.plist file), my simulators downloaded fine, but then they disappeared again after I rebooted my machine.
Hi All, I do have the same issue. Tried everything with the help of AI ... no success. Filed two complaints @ ... no answer. How could your QA not find this? My complete update plan for my apps is completely screwed now ... Please fix this asap!
Have been dealing with this too. Incredibly frustrating.
I also have this problem and I am going crazy, did a full macos restore (didn't wipe the HD yet) and it keeps doing that. Also noticed every 11 seconds a new SimRuntimeBundle is created in Macintosh HD > Library > Developer > CoreSimulator > Cryptex > Images > mnt folder very strange indeed.
As diniska wrote, this is what finally worked for me:
You do need to reboot in recovery, turn off SIP, do the deletion, reboot in recovery, turn on SIP, and reboot. But it's been working ever since.
Here is a summary of my findings so far working with AI:
The Bug: macOS Tahoe 26.4 triggers a loop in the CoreSimulator subsystem where a new SimRuntimeBundle is created in /Library/Developer/CoreSimulator/Cryptex/Images/mnt/ every 11 seconds. This accumulates thousands of files and bloats the images.plist manifest.
Why Xcode Hangs: When Xcode launches, it starts CoreSimulatorService, which spawns a helper daemon called simdiskimaged via XPC. simdiskimaged is responsible for managing simulator disk images and runtimes. On startup, it tries to load and validate the entire contents of images.plist and the Cryptex directory. Because of the runaway loop, there are now 7,000+ files and a bloated manifest to parse. simdiskimaged exceeds its hardcoded 20MB jetsam memory limit and gets killed by the system (SIGKILL/-9). CoreSimulatorService sent a synchronous XPC message to simdiskimaged and is now waiting for a reply that will never come — it hangs forever on mach_msg2_trap. Everything downstream hangs: xcrun simctl, Xcode's SDK detection, simulator availability — all of it.
The Evidence: simdiskimaged was killed 1,165 times with exit reason JETSAM_REASON_MEMORY_PERPROCESSLIMIT
Its jetsam limit is 20MB active / 15MB inactive
The CoreSimulatorService stack trace shows a single thread blocked on SimDiskImageManager serviceVersionWithError: → xpc_connection_send_message_with_reply_sync → mach_msg2_trap
The service is programmatically submitted by CoreSimulatorService (no on-disk plist), so the memory limit can't be user-configured
Ok, here is my step by step (what I think is) a solution guide... (worked for me)
Fix: Xcode Hangs on macOS Tahoe 26.4 (SDKs "Status Unavailable")
The Problem
macOS Tahoe 26.4 introduces a bug where a CoreSimulator subprocess (simdiskimaged) repeatedly exceeds its 20MB memory limit and gets killed by the system. This causes CoreSimulatorService to hang indefinitely, which in turn causes Xcode to freeze, SDKs to show "status unavailable," and all simulators to become inaccessible.
The root cause is a runaway loop that creates new SimRuntimeBundle files every 11 seconds in /Library/Developer/CoreSimulator/Cryptex/Images/mnt/, bloating the state that simdiskimaged must load on startup beyond its jetsam memory limit.
The Fix
Step 1 — Grant Terminal Full Disk Access
The files that need to be deleted are protected by TCC (Transparency, Consent, and Control). Without this step, sudo rm will return "Operation not permitted."
/Applications/Utilities/)Step 2 — Force Quit Xcode
Close Xcode completely. Force Quit if necessary.
Step 3 — Delete the Corrupted CoreSimulator State
Run the following commands in Terminal:
sudo rm /Library/Developer/CoreSimulator/Images/images.plist
sudo rm -rf /Library/Developer/CoreSimulator/Cryptex
Step 4 — Reboot
Restart your Mac.
Step 5 — Verify the Fix
Open Terminal and run:
xcrun simctl list devices
This should return a list of devices (marked "unavailable") without hanging. If it responds, the daemon is healthy again.
Step 6 — Clean Up Stale Runtime Data
Before re-downloading runtimes, clear any stale references that may cause duplicate errors:
xcrun simctl runtime delete all
sudo rm -rf /Library/Developer/CoreSimulator/Images/
sudo rm -rf ~/Library/Developer/CoreSimulator/Devices/
Step 7 — Re-Download Simulator Runtimes
Xcode should now function normally.
Notes
simdiskimaged and the uncapped SimRuntimeBundle creation loop.CoreSimulatorService, tracing it to the killed simdiskimaged daemon, and discovering the jetsam memory pressure caused by accumulated runtime state.We got this problem on our CI machines after updating to macOS 26.4. Solution with removing images.plist file lasted only for one build.
We did downgrade macOS to 26.3 and it helped. Hope this nightmare will fix in next releases.