Fixing ‘Unable to Access Default Device–Set’ in Xcode

TL;DR

If you encounter “Unable to access default device–set” when creating simulators in Xcode, fix directory ownership:

sudo chown -R $(whoami):staff ~/Library/Developer

Restart XCode

Then reimport the simulator runtime and recreate your simulators.

The Problem

When attempting to create a new simulator in Xcode, you may encounter:

Unable to access default device–set

This error occurs due to permission issues with the ~/Library/Developer/CoreSimulator/Devices directory. Apple Developer Forums discuss this issue (thread 1, thread 2), but lack clear solutions.

Troubleshooting Steps

I attempted several fixes that didn’t work:

• Restarting the Mac
• Reinstalling Xcode
• Changing the xcode-select path:

  sudo xcode-select -s ~/Downloads/Xcode.app/
  

• Manually installing the Simulator runtime (guide)

Root Cause

Running these commands failed with permission errors:

xcrun simctl list devices
xcodebuild -importPlatform ~/Downloads/iOS_18.2_Simulator_Runtime.dmg

The error logs revealed:

Error Domain=com.apple.CoreSimulator.SimError Code=400 "Unable to determine SimDeviceSet for subscriptions, set_path=~/Library/Developer/CoreSimulator/Devices"

The ~/Library/Developer directory was owned by root instead of your user:

mkdir ~/Library/Developer/CoreSimulator
# Permission denied

The Solution

Change ownership to match your ~/Library directory:

ll ~/Library
# drwx------@ 101 paul  staff  3232  7 Feb 08:01 Library

sudo chown -R paul:staff ~/Library/Developer

Then reimport the simulator runtime:

xcodebuild -importPlatform ~/Downloads/iOS_18.2_Simulator_Runtime.dmg

Success:

importing ~/Downloads/iOS_18.2_Simulator_Runtime.dmg
Registered as 9A66D486-5FAE-436A-B0E3-DC2AA9F9****.

You can now create simulators via Xcode → Window → Devices and Simulators → +.