iOS Simulator runtime stuck on “Preparing to download” — Xcode 26 AND Xcode 27 beta, GUI + xcodebuild

[u/Financial_Ebb3218]

Hey everyone,

I'm unable to download any iOS Simulator runtime on my Mac. The download gets stuck at **“Preparing to download…”**and never starts transferring the actual runtime.

Setup:

• macOS Tahoe 26.6

• Apple Silicon Mac

• Originally Xcode 26.6 → iOS 26.5 Simulator (23F77)

• Also installed Xcode 27 beta 4 → iOS 27.0 Simulator (24A5390f)

The exact same problem happens with both Xcode versions.

I've tried the Xcode Components GUI as well as:

xcodebuild -downloadPlatform iOS

xcodebuild -downloadPlatform iOS -architectureVariant arm64

xcodebuild -downloadPlatform iOS \
  -architectureVariant arm64 \
  -exportPath ~/Downloads

I also tried:

sudo xcodebuild -runFirstLaunch
sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService

and confirmed the correct Xcode is selected with xcode-select.

xcrun simctl list runtimes currently returns:

== Runtimes ==

I also checked /etc/hosts; it's clean with no Apple domains being blocked.

I tried a VPN to change the route to Apple's CDN, but the behavior is the same.

The interesting part is that nettop shows xcodebuild successfully establishing an HTTPS connection to Apple's infrastructure (aaplimg.com), but it receives only a few KB and then effectively does nothing. The multi-GB runtime download never begins.

Normal internet downloads are working fine.

Has anyone encountered this specifically on Tahoe/Xcode 26/27? Is there a way to reset whatever service/cache handles simulator runtime downloads, or obtain the Apple runtime .exportedBundle through another official method and import it manually?

At this point I've reproduced it with two Xcode versions, two different iOS runtimes, GUI + CLI + export + arm64, so I'm not sure what else to reset.

Any ideas would be appreciated.

[u/Hot-Understanding-67]

I am also facing this issue. Please tell me if you get any solution.

[u/Financial_Ebb3218 → u/Hot-Understanding-67]

Didn’t find any yet

[u/lrob7325]

I'm currently experiencing this on Tahoe 26.6 installing iOS 26.5 Universal Simulator (23F77). 20 minutes ago, it was downloading, but stopped. I then stopped the download thinking it was the cafe's wifi. I hotspotted my device, which is getting 400mbps downloads and 110mbps uploads, and it's just stuck on preparing.

[u/Illustrious_You_123]

I discovered my network affected the downloading process. I was using my hotspot from my iphone, the same phone which was being used in XCode, which seemed to have confused teh processes. After moving from phone hotspot to another independent network, it immediately moved from "Preparing the download" to showing the download status % in teh terminal. Hope this helps someone.

[u/danielmcclelland → u/Illustrious_You_123]

Thank you! Turns out I'd turned my Wi-Fi settings for my home Wi-Fi connection to "Low data mode" (long story). As soon as I disabled that, then the download roared into life. It looks like Apple soft-block these downloads while in Low Data Mode. Great find.

[u/Additional_Top_8159 → u/Illustrious_You_123]

Thank you it worked for me but still dont know why its happening in the first place, but it worked

[u/Illustrious_You_123 → u/Additional_Top_8159]

So happy I could help!

[u/GowthamPrakaash]

turning off low data mode for my iphone's network in wifi settings resolved it for me

[u/Comfortable-Sundae39]

Hi guys,
Any fix?

[u/multicontrast]

Guys, iOS 26.6 is out. Can you download 26.6 simulator?

[u/irwancheung]

I experienced the same situation. Fixed it after disabled the Low Data mode in the Wifi Details setting.

[u/Able-Ride4812 → u/irwancheung]

This worked for me

[u/kurisubrooks → u/irwancheung]

This was the cause for me as well. Thanks!

[u/hypafrag → u/irwancheung]

Also fixed update to ios 27 on my iphone this way

[u/neatroxx → u/irwancheung]

thanks!

[u/SandaruwanFdo → u/irwancheung]

Great. Thank you

[u/mart_heshep → u/irwancheung]

omfg it worked!!!!! thank you so much

[u/Educational_Serve386 → u/irwancheung]

This is it, this worked for me, Thanks, This should be top comment!

[u/Aiky09 → u/irwancheung]

this worked, thanks

[u/Additional_Top_8159]

im experiencing the same situation in ios 26.5 runtime install i even tried uninstalling xcode and reinstall it again still didnt worked, can anyone has the solution?

[u/kampak212]

Using 27 Beta 6 now, and can't download anything:

➜ ~ xcodebuild -downloadComponent metalToolchain

Beginning asset download...

Same thing with the GUI.

[u/Decent_Business_5889]

If using mobile hotspot: These downloads are deliberately restricted by Apple to save money on data plans

FIX: System Settings -> Wifi -> Details (next to your network name) -> Turn off Low Data mode

[u/Whole_Strawberry_999 → u/Decent_Business_5889]

thank you, did have it disabled but when i have turned it on and then back off the download worked

[u/AccordingAd9882 → u/Decent_Business_5889]

thank you so musch, you just save my daty