Intermittent `...\\Microsoft VS Code\\NUL` access-denied dialog when Copilot Chat is triggered via voice-command workflow on Windows

[Mark-Phillipson]

Type: Bug

I am intermittently getting this error on Windows when sending voice commands via Bob that bring VS Code / Copilot Chat into focus:

There was an error while Opening file handle:
C:\Users<user>\AppData\Local\Programs\Microsoft VS Code\NUL
Failed to create file handle: Access is denied.
Please verify there are no Visual Studio Code processes still executing.

This looks related to:

• Periodically getting access denied error while navigating between sessions vscode#304313
• Auto-updater fails with "Failed to create file handle: Access is denied" on \NUL path (VS Code Insiders, Windows) vscode#305276
• fix: use os.devNull for OTel null sink #4748

Why I am filing this:
I understand there was already a fix for a Windows NUL null-sink issue in Copilot Chat, but I am still seeing a very similar error intermittently in a voice-command workflow.

My setup:

• Windows
• VS Code
• GitHub Copilot Chat
• A local assistant app ("Bob") that can trigger/focus VS Code and send voice-command-driven prompts

Important detail:
My local app is not constructing a ...\Microsoft VS Code\NUL path itself. On my side it is only launching VS Code / interacting with Copilot Chat. The NUL path appears in the VS Code error dialog.

Observed behavior:

• The issue is intermittent
• It appeared while sending voice commands through Bob
• A full machine restart helped with some broader VS Code/Copilot UI oddities, but this NUL access-denied issue has still occurred intermittently
• It seems related to VS Code / Copilot Chat activity rather than my app logic

Expected behavior:

• No attempt to open or create a literal NUL path in the VS Code install directory
• No access-denied dialog during Copilot Chat / voice-command workflows

Actual behavior:

• VS Code shows an error dialog referencing:
  C:\Users<user>\AppData\Local\Programs\Microsoft VS Code\NUL

Notes:

• I can provide screenshots
• I can also provide exact VS Code and Copilot Chat versions if needed
• If this should instead be tracked in microsoft/vscode again, please redirect me and I will repost there

[Mark-Phillipson]

[robincodex]

I also encountered this write error, but I wasn't using voice commands — I simply updated the extension. In the end, I had to delete the NUL file using Del "\?\C:\Users\robin\AppData\Local\Programs\Microsoft VS Code\NUL".

Now the latest version 0.42.2 causes my CPU to spike abnormally on my machine, and even VS Code's IntelliSense (code suggestions) starts to lag. This forced me to roll back to version 0.41.1, The 0.41.2 version also has this issue.

[Mark-Phillipson]

As a workaround I uninstalled Visual Studio Code and then renamed the folder because it left behind this file and then reinstalled Visual Studio Code and it seems to be working but I've still got that file that I cannot delete normally

[bloodycop6385]

Experiencing this as well