Device Support for macOS 26 / Mobile Device Support

Attempting to install macOS 26 Tahoe in UTM on a macOS 15 Sequoia host returned:

Error

A software update is required to complete the installation. Installation requires a software update.

In some cases, the following window would also appear:

A software update is required to install macOS in a virtual machine.

Would you like to download and install this update now?

Use of this software is subject to the original Software License Agreements) that accompanied the software being updated.

Learn More… | Not Now | Install

Clicking "Install" resulted in:

Installation failed

Can't install the software because it is not currently available from the Software Update server.

Preferred updating "Device Support for macOS 26"/"Mobile Device Support" to installing a new version of Xcode, but it was missing from developer.apple.com. Expected that it must be in the Xcode installer:

1. Downloaded Xcode_26_Release_Candidate_Apple_silicon.xip

2. Unpacked with unxip (2-3x faster than Archive Utility)

3. Searched for "Mobile*" under Xcode.app/Contents/ via Find Any File, unearthing MobileDevice.pkg in Xcode.app/Contents/Resources/Packages/

4. After running MobileDevice.pkg (13897894 bytes, SHA256: 305ddeb575c7f85e76f83c1fd5d20d0de34538bb9a61113db041fb4deab12363), Tahoe installation in UTM proceeded normally (searching online for MobileDevice.pkg confirmed it had worked for others as well)

❧ 2025-09-15