[BUG] Claude Code for VS Code extension fails to work since 2.1.73 upgrade

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code pane on the sidebar shows "An error occurred while loading view: claudeVSCodeSidebarSecondary".

Open a new tab by clicking on the Claude Code Icon, it is spinning on "Loading sessions..."

Using Command "Claude Code: Open in New Tab" resulted in "v is not iterable".

Followed the instructions from Claude as described below. None of the solution works.

Step 1 — Full reload first
Open the Command Palette (Ctrl+Shift+P) and run Developer: Reload Window. Sometimes the extension context keys don't get set on first activation and a reload clears it.
Step 2 — Open Claude via Command Palette directly
Run Claude Code: Open in New Tab from the Command Palette. If this works, the sidebar view registration is the issue rather than the extension itself being broken.
Step 3 — Clear cached extension state
Close VS Code completely, then delete the extension's webview storage. On Windows, this is typically at:
%APPDATA%\Code\User\workspaceStorage\
Look for folders related to anthropic.claude-code and delete them. Restart VS Code. This forces the webview panels to be freshly created rather than deserialized from a potentially corrupt state.
Step 4 — Check if Claude Desktop is running simultaneously
If you have Claude Desktop open at the same time as VS Code, try closing it completely and see if the sessions list loads. There's an active bug where using the VS Code extension and Claude Desktop Code mode simultaneously/interchangeably on the same Windows machine causes sessions to repeatedly disappear. GitHub
Step 5 — Reinstall the extension cleanly
Uninstall the extension from VS Code, then also update the CLI in PowerShell:
powershellnpm update -g @anthropic-ai/claude-code
Then reinstall the extension fresh from the Marketplace.

What Should Happen?

It should work in the tab in the sidebar.

Error Messages/Logs

Sidebar: An error occurred while loading view: claudeVSCodeSidebarSecondary
New tab by clicking on the icon: Loading sessions
New tab by command: v is not iterable.

Steps to Reproduce

1. Open the CLAUDE CODE tab on the sidebar.
2. Open Claude Code tab by clicking on the Claude icon.
3. Ctrl-Shift-P and select Claude Code: Open in New Tab.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.72

Claude Code Version

2.1.76

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Revert back to 2.1.71 did not resolve the problems.
Running cli in the powershell terminal works.