It took quite a sequence of topics to understand this issue. To boil it down, Swift 5 binaries built with Xcode 10.2 require the Swift 5 Runtime Support for Command Line Tools, which are not included in macOS < 10.14.4 (must be directly downloaded from More Downloads in Apple Developer). As of 11 da…

I just ran into this problem as well. Is there an ETA for them to update to 10.14.4?

Looks like this has also been raised on this thread: https://discuss.circleci.com/t/xcode-10-2-image-released/29761/3

Latest Xcode image (10.2) has drawbacks with the image OS (10.14.3)

drazisil April 15, 2019, 9:43pm 4

Keeping discussion to one thread: Xcode 10.2 image released

Topic		Replies	Views
Xcode 10.2 image released Announcements ios , macos	23	8190	May 20, 2019
When is Xcode 10.2 support coming up? Build Environment xcode	11	4159	April 15, 2019
Xcode 10.2 support (Coomand line tools) Mobile xcodebuild	4	1972	April 5, 2019
Xcode 10.0 GM Image Released Announcements build-image , ios , xcode , macos	24	7525	November 7, 2018
Xcode 14.2 Released [Breaking Changes] Announcements xcode	26	8115	April 26, 2023