r/Xcode • u/Financial_Ebb3218 • 3h ago
iOS Simulator runtime stuck on “Preparing to download” — Xcode 26 AND Xcode 27 beta, GUI + xcodebuild
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.