Extension activation causes VSCode's Extension Host to crash

[paulpe-rr]

Describe the bug

Opening or creating any YAML file (empty or not) causes the VSCode extension host to crash.

Expected Behavior

The extension should work and not make the extension host crash.

Current Behavior

• Extension Host behaves as expected until a YAML file is opened (existing or after creation).
• Extension Host doesn't recover by itself until the VSCode window is reloaded.
• The content of the file doesn't matter (also occurs on empty files).
• This also occurs on a blank VSCode window, opening a single YAML file.
• VSCode's Developer Tools logs: developer-tools-logs.txt.
• VSCode's Output View doesn't list the extension, so no logs there.
• Installing different versions of the extension doesn't seem to change anything, I tried with those versions:
  • 1.24.2026052009 (pre-release)
  • 1.23
  • 1.15 (which I knew to be working on my machine prior)
  • 1.14 (which I knew to be working on my machine prior)

Steps to Reproduce

1. Open any YAML file with VSCode

Has been tested on a new VSCode profile, with blank {} User and Workspace settings, and only the single redhat.vscode-yaml extension installed.

Environment

• Windows 11 x64 10.0.26200
• VSCode 1.121.0
• Node.js 22.22.1

[datho7561]

I can't replicate this on Linux. I'll have to sit down at my Windows computer at some point to see if I can replicate there.

[scorder96]

To add to this,

expo.vscode-expo-tools, which uses redhat.vscode-yaml as a dependency, expands this issue to more file types. I tested it with .html, .css, .tsx, and .py files. The extension host crashes without needing to open any YAML file.

When checking running extensions, YAML extension is stuck on "Activating..." state, with the error message: "Cannot register 'redhat.telemetry.enabled'. This property is already registered."

Edit: After a computer restart and WSL update (if that matters), I can't reproduce the bug. The extension host doesn't crash anymore and the extension state is now activated. However, the error message still remains.

[datho7561]

"Cannot register 'redhat.telemetry.enabled'. This property is already registered." is unrelated and should be harmless. I'll try on my Windows computer today.

[datho7561]

I can't replicate this on Windows