How to Fix Xcode “Download Was Cancelled” Exit Code 70 When Installing an iOS Simulator

When Xcode tries to install an iOS Simulator runtime, the Components pane may remain on “Preparing…” while the command line ends with “Download was cancelled” and exit code 70.

In September 2026, developers reported this behavior with macOS Tahoe 26.6, Xcode 26.6, and the iOS 26.5 Simulator runtime on Apple Developer Forums. However, exit code 70 can also result from selecting the wrong Xcode, insufficient temporary space, network filtering, or an Apple delivery problem, so troubleshoot it systematically.

Typical symptoms
The SDK and Simulator runtime are different
Fix 1: Retry from Xcode Components
Fix 2: Verify the selected Xcode
Fix 3: Download from the command line
Fix 4: Check connectivity and storage
Fix 5: Use another compatible runtime or Xcode release
Be careful with manual deletion
How to verify the result
When this occurs on Xcode 26.6
Summary

Typical symptoms

xcodebuild -downloadPlatform iOS

Finding content...
Download was cancelled
exit code 70

Xcode Settings > Components may stay at “Preparing…” indefinitely. The simulator SDK can still be present, allowing compilation, while simulator launch and tests remain unavailable because no runtime is installed.

The SDK and Simulator runtime are different

An iphonesimulator entry in xcodebuild -showsdks does not prove that an executable Simulator runtime is installed.

xcodebuild -showsdks
xcrun simctl list runtimes

If the SDK appears but simctl list runtimes is empty or reports unavailable runtimes, the runtime download or registration did not complete.

Fix 1: Retry from Xcode Components

Open Xcode.
Choose Xcode > Settings > Components.
Start the required iOS Simulator runtime download.
If the state never changes, quit Xcode completely and open it again.

Apple’s documentation identifies the Components settings as the supported interface for installing additional platforms and simulator runtimes.

Fix 2: Verify the selected Xcode

When multiple Xcode versions are installed, Terminal may point to a different developer directory.

xcode-select -p
xcodebuild -version

Select the intended standard Xcode installation when necessary.

sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

Then complete first-launch setup and license processing.

sudo xcodebuild -runFirstLaunch

Fix 3: Download from the command line

If the graphical download does not progress, use Apple’s xcodebuild command.

xcodebuild -downloadPlatform iOS

On supported Xcode versions, export the downloaded runtime to a directory and import it separately.

mkdir -p "$HOME/Downloads/XcodePlatforms"

xcodebuild -downloadPlatform iOS \
  -exportPath "$HOME/Downloads/XcodePlatforms"

After confirming the exact downloaded .dmg or .simruntime path, import it.

xcodebuild -importPlatform "/path/to/runtime.dmg"

If the export directory remains empty, the failure occurred before a usable runtime file was created. Passing a nonexistent file to -importPlatform will not help.

Fix 4: Check connectivity and storage

Simulator runtimes are large and require additional temporary space while being expanded.

df -h /
date
curl -I https://gdmf.apple.com/

Also check the following:

Temporarily isolate VPN, proxy, filtered DNS, and firewall behavior.
Try another network when using a corporate or school connection.
Set macOS date and time automatically.
Check Apple’s system status.
Restart the Mac and retry with only Xcode open.

Successful basic connectivity does not rule out a problem with Apple’s runtime metadata or a particular runtime asset.

Fix 5: Use another compatible runtime or Xcode release

If only one Xcode/runtime combination fails, check whether Components offers another runtime compatible with the project. If CI and testing requirements permit, temporarily using the preceding stable Xcode can help isolate a release-specific problem.

Before keeping an older Xcode, verify current App Store submission and SDK requirements. Prefer a newer corrected Xcode release when Apple makes one available.

Be careful with manual deletion

Do not indiscriminately delete /Library/Developer/CoreSimulator or MobileAsset system data. Manual deletion can damage installed runtimes and existing simulator devices. Start with Components, supported commands, restart, and network checks.

To remove only simulator devices whose runtimes are already unavailable, use:

xcrun simctl delete unavailable

This cleanup command does not repair a runtime download failure.

How to verify the result

Confirm the developer directory with xcode-select -p.
Confirm the runtime appears in xcrun simctl list runtimes.
Check that Xcode lists simulator run destinations.
Create and boot a new simulator.
Build and run the project’s tests.

When this occurs on Xcode 26.6

An Apple Developer Forums report from September 2026 documents the failure on macOS Tahoe 26.6, Xcode 26.6 build 17F113, and the iOS 26.5 Simulator even after checking free space and Apple server connectivity.

As of September 16, 2026, that thread does not provide an Apple-confirmed fixed build or definitive recovery procedure. If your environment matches and all basic checks pass, avoid destructive system-cache changes. Submit diagnostics through Feedback Assistant and watch for an Xcode update or restoration of the affected runtime asset.

Summary

For “Download was cancelled exit code 70,” first distinguish an installed SDK from a missing runtime, verify the selected Xcode, retry Components, and check space and networking. Use xcodebuild -downloadPlatform iOS and the supported export/import path when available. Because Xcode 26.6 and iOS 26.5 still had reports in September 2026, another compatible runtime or a corrected Xcode release may be required after local checks are exhausted.

References: Downloading and installing additional Xcode components / Apple Developer Forums: Xcode 26.6 cannot download iOS 26.5 Simulator runtime