Switch Windows build pools from VS2022 to VS2026 preview

[Copilot]

Description

Updates Windows build pool images from VS2022 to VS2026 preview across CI pipelines, including main build infrastructure and stress test pipelines.

Changes

• eng/pipelines/common/xplat-setup.yml:

  • Official builds: windows.vs2022.amd64 → windows.vs2026preview.scout.amd64
  • Public builds: windows.vs2022.amd64.open → windows.vs2026preview.scout.amd64.open

• eng/pipelines/libraries/fuzzing/deploy-to-onefuzz.yml:

  • Fuzzing jobs: windows.vs2022.amd64 → windows.vs2026preview.scout.amd64

• eng/pipelines/libraries/stress/ssl.yml:

  • SSL stress tests: 1es-windows-2022-open → windows.vs2026preview.scout.amd64.open

• eng/pipelines/libraries/stress/http.yml:

  • HTTP stress tests: 1es-windows-2022-open → windows.vs2026preview.scout.amd64.open

All VS2022 and 1es-windows-2022 image references in pipeline configurations have been migrated to the VS2026 preview scout image.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Switch from VS2022 to VS2026 image</issue_title>
<issue_description>At least in main but probably also in release/10.0.</issue_description>

<agent_instructions>Let's start by changing the public and official build windows pools to windows.vs2026preview.scout.amd64. That should be found in eng/pipelines/common/xplat-setup.yml. We'll figure out whatever else is needed as we go.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Switch from VS2022 to VS2026 image #123550

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[Copilot]

Pull request overview

This PR migrates Windows CI build pool images from Visual Studio 2022 to Visual Studio 2026 preview across Azure DevOps pipelines. The change aligns the build infrastructure with the latest tooling as requested in issue #123550.

Changes:

• Updated official and public Windows build pools from windows.vs2022.amd64 to windows.vs2026preview.scout.amd64
• Updated fuzzing pipeline Windows build pool to use the same VS2026 preview image

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
eng/pipelines/common/xplat-setup.yml	Updated official and public Windows build pool images from VS2022 to VS2026 preview scout
eng/pipelines/libraries/fuzzing/deploy-to-onefuzz.yml	Updated fuzzing job Windows build pool from VS2022 to VS2026 preview scout

[hoyosjs]

@copilot - can you also please change the SSL stress pipelines of the 1es-windows images to these ones please.

[Copilot]

@copilot - can you also please change the SSL stress pipelines of the 1es-windows images to these ones please.

Done! Updated both SSL and HTTP stress pipelines from 1es-windows-2022-open to windows.vs2026preview.scout.amd64.open in commit bdf0fc0.

[steveisok]

@copilot I'd like to create a follow up issue for us to move to a prod VS2026 build image when it becomes available. Can you sketch out some text for me to copy?

[Copilot]

@copilot I'd like to create a follow up issue for us to move to a prod VS2026 build image when it becomes available. Can you sketch out some text for me to copy?

Here's a draft for the follow-up issue:

---

Title: Migrate from VS2026 Preview Scout to production VS2026 build image

Description:

We currently use the VS2026 preview scout image (windows.vs2026preview.scout.amd64) across our Windows build pools. Once the production VS2026 image becomes available, we should migrate to it for stability and long-term support.

Files to update:

• eng/pipelines/common/xplat-setup.yml - Official and public Windows build pools
• eng/pipelines/libraries/fuzzing/deploy-to-onefuzz.yml - Fuzzing job pool
• eng/pipelines/libraries/stress/ssl.yml - SSL stress test pool
• eng/pipelines/libraries/stress/http.yml - HTTP stress test pool

Expected changes:

• windows.vs2026preview.scout.amd64 → windows.vs2026.amd64
• windows.vs2026preview.scout.amd64.open → windows.vs2026.amd64.open

Labels: area-Infrastructure, os-windows

---

[steveisok]

/ba-g Known issue dotnet/dnceng#1886 and wasm ones unrelated.