[macOS] DOTNET_ROOT environment variable variable will be removed on January 12th, 2026 #13470
Description
Breaking changes
The DOTNET_ROOT variable will be removed from the image environment.
Target date
Image deployment will start on Monday January 12th, 2026 and will take about 3 days.
The motivation for the changes
As described in the issue: #13365
The DOTNET_ROOT environment variable is no longer set by default to avoid interfering with .NET SDK discovery and version resolution. Modern .NET tooling is able to locate installed SDKs without relying on this variable, and keeping it predefined has caused inconsistent behavior across workflows.
Possible impact
Workflows that explicitly rely on DOTNET_ROOT being predefined may fail to locate the expected .NET SDK version and will require setting this variable manually.
Platforms affected
- Azure DevOps
- GitHub Actions
Runner images affected
- Ubuntu 22.04
- Ubuntu 24.04
- Ubuntu Slim
- macOS 14
- macOS 14 Arm64
- macOS 15
- macOS 15 Arm64
- macOS 26 Arm64
- Windows Server 2019
- Windows Server 2022
- Windows Server 2025
Mitigation ways
If you see any issues with your workflows, you may do one of the next steps:
- Set the variable manually, for example use in the same job/step:
export DOTNET_ROOT=$HOME/.dotnet