[OUTDATED] iOS 26.5 unavailable for builds in TeamCity Cloud using JetBrains macOs agents

The fixed image has been deployed. Article kept in case the issue happens in the future.

Symptoms:

• Runs that depend on iOS 26.5 fail to detect the runtime as available

Cause:

• There is a process on agent start that detects the available runtimes
• At the point that the build starts, this process hasn't finished, so the application doesn't have access to them
• For some reason, the available runtimes aren't updated as they are detected, and the

Workaround:

• Run xcrun simctl runtime scan-and-mount at the start of the build - This updates the xcode library of available runtimes. It might still have timing issues, if those happen, it might need a delay.
• xcodebuild -downloadPlatform iOS can be used to test for its presence before running the scan-and-mount

Resolution:

A new image that will have the runtimes ready at build time is being currently created and deployed.