[BUG] Claude Desktop 1.1.4173 crashes on startup on Windows (Squirrel install, sv-SE locale)

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?

Bug description

Claude Desktop v1.1.4173 silently crashes on startup on Windows when installed via the Squirrel installer (not
MSIX/Windows Store). The app process starts but no window is ever shown.

## Root cause (already diagnosed)
The main process throws an unhandled promise rejection before the window is created:

Error: [@formatjs/intl] An id must be provided to format a message.
at nZe (.vite/build/index.js:83)
at Sae (.vite/build/index.js:83)
at WOt (.vite/build/index.js:705)

In WOt() (the Cowork/yukonSilver VM support check), the branch for Windows + non-MSIX installs calls
Ue.formatMessage({ defaultMessage: "Cowork requires Claude Desktop be installed with our modern installer" })
without an id field, which @formatjs/intl requires. This missing id throws and prevents window creation.

The same bug exists for all other formatMessage calls in WOt(), but this is the only branch triggered for this
configuration.

## Environment

• OS: Windows 11 Home 10.0.26200
• Claude Desktop version: 1.1.4173
• Install method: Squirrel (not MSIX/Windows Store)
• System locale: sv-SE (Swedish)
• CPU: Intel Core i9-14900KF

## Steps to reproduce

1. Install Claude Desktop via the standard Windows installer (Squirrel)
2. Set Windows system locale to sv-SE (or possibly any locale without a bundled .json file)
3. Upgrade to v1.1.4173
4. Launch Claude Desktop → no window appears

## Fix
Add an id field to all formatMessage() calls in WOt() in the main process bundle, e.g.:
Ue.formatMessage({ id: "cowork.msix_required", defaultMessage: "Cowork requires Claude Desktop be installed with our
modern installer" })

What Should Happen?

Claude Desktop should launch normally and display the main window. The Cowork/yukonSilver feature being unsupported on
non-MSIX Windows installs should be handled gracefully (returning the unsupported status silently) rather than
throwing an unhandled exception that prevents the entire app from starting.

Error Messages/Logs

Claude Desktop should launch normally and display the main window. The Cowork/yukonSilver feature being unsupported on
   non-MSIX Windows installs should be handled gracefully (returning the unsupported status silently) rather than
  throwing an unhandled exception that prevents the entire app from starting.

Steps to Reproduce

1. Install Claude Desktop via the standard Windows installer (Squirrel, not MSIX/Windows Store)
2. Set Windows system locale to sv-SE (or any locale without a bundled translation file)
3. Upgrade to v1.1.4173
4. Launch Claude Desktop — no window appears, app runs silently in background with 4 processes but is completely

unusable

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.1.4173

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

main.log