Claude Desktop v1.1.4173 renderer fails to start on Windows 10 LTSC 2019 (Electron 40)

Bug Description

After auto-updating from v1.1.4088 to v1.1.4173, Claude Desktop no longer renders its UI on Windows 10 Enterprise N LTSC 2019 (build 17763). The main Electron process starts but the renderer process never spawns, resulting in no visible window/UI.

Environment

• Claude Desktop version: 1.1.4173 (was working on 1.1.4088)
• Electron version: 40.4.1
• Node version: 24.13.0
• OS: Windows 10 Enterprise N LTSC 2019 (10.0.17763)
• CPU: Intel Core i7-10850H @ 2.70GHz
• RAM: 64GB

Steps to Reproduce

1. Have Claude Desktop v1.1.4088 running on Windows 10 LTSC 2019
2. Auto-update to v1.1.4173 is applied (via Squirrel)
3. App restarts with the new version
4. No UI appears

Observed Behavior

• The main Electron process starts successfully (logs Starting app { appVersion: '1.1.4173' })
• Crashpad handler, GPU process, and network service processes all start
• No renderer process is created (--type=renderer absent from process list)
• claude.ai-web.log has zero entries after the update (renderer never initializes)
• Two Sentry errors logged immediately on startup:

``
[@formatjs/intl] An id must be provided to format a message.
``

• Multiple launch attempts all result in secondary instances detecting "Not main instance, returning early from app ready"
• Previous version (v1.1.4088) was working normally on the same system

Expected Behavior

Claude Desktop should render its UI and be usable after the update.

Log Evidence

From main.log at startup (2026-02-27 09:29):

2026-02-27 09:29:26 [info] Starting app { appVersion: '1.1.4173', isPackaged: true, platform: 'win32', arch: 'x64', nodeVersion: '24.13.0' }
2026-02-27 09:29:28 [error] Sentry caught: { eventId: '36bcf7cc1da54ef4bf8f3d8c179e0bf1', type: 'Error', value: '[@formatjs/intl] An `id` must be provided to format a message...' }

Process list shows only main + crashpad + GPU + network, no renderer:

app-1.1.4173\claude.exe                    (main process)
app-1.1.4173\claude.exe --type=crashpad-handler
app-1.1.4173\claude.exe --type=gpu-process
app-1.1.4173\claude.exe --type=utility --utility-sub-type=network.mojom.NetworkService

Suspected Root Cause

The upgrade to Electron 40.4.1 may have compatibility issues with Windows 10 LTSC 2019 (build 17763, October 2018 feature update). The renderer process fails silently on this older Windows build. The previous version (1.1.4088) worked fine on the same system.

Workaround

The old version directory app-1.1.4088 is still present on disk. Rolling back to it may restore functionality (not yet tested).