[BUG] Claude Desktop (Store/MSIX install, Windows 11) – blank screen on launch due to repeated title bar overlay failures

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 Desktop opens to a completely blank window on every launch. The window frame appears but no content is rendered. The app is running (taskbar icon is present, Ctrl+Alt+Space quick input overlay works) but the main window never paints.

Only known workaround: Press Ctrl+Alt+Space to open the quick input overlay, type a message, wait for a response — this triggers a repaint and the main window becomes visible. Standard workarounds (minimise/restore, Win+Left/Right snap, Alt+Tab) have no effect.

A secondary issue: a popup error "No organization found for image upload" appears on every launch. Auth is succeeding and an orgId is present, so this appears to be a race condition where the image upload service initialises before account data is available.

What I've already tried

• Multiple reinstalls (5–6 attempts across versions including latest update) — no effect
• Cache deletion (%AppData%\Claude\Cache) — no effect
• Display scaling changed from 150% to 100% — no effect
• Window state file inspected — dimensions and position are valid, not the cause
• Compatibility flags (disable fullscreen optimisations, GPU override) — not accessible; Store/MSIX install has no .exe in the package folder and no Compatibility tab available on the shortcut
• --disable-gpu launch flag — not possible; shell:AppsFolder launches do not pass arguments to Store-packaged apps

Root cause hypothesis

The title bar overlay API is failing repeatedly in the Store-packaged Electron build on Windows 11, preventing the main window from completing its initial render. The event loop stalls during the startup VM download compound the issue by blocking the UI thread. Because this is a Store/MSIX install, standard Electron workarounds (CLI flags, compatibility mode settings) are inaccessible to the end user.

What Should Happen?

Main window renders on launch without requiring a manual repaint trigger.

Error Messages/Logs

## Log analysis

From `%AppData%\Claude\logs\main.log`, the following line appears **10+ times per session**, in pairs, each time a window attempts to render:


Failed to set title bar overlay, this is probably expected


This correlates directly with every launch and every subsequent window open event. The comment "probably expected" suggests this is handled elsewhere, but the frequency here (10+ occurrences vs occasional in normal installs) indicates it is not being handled correctly in this context and is the likely cause of the blank window.

Additionally, significant **event loop stalls** are logged during startup — 26+ seconds cumulative, with individual blocks up to 2 seconds — coinciding with a background VM image download (~1.27GB for Claude Code/Cowork). This compounds the rendering issue by starving the UI thread during the critical initial paint window.

Relevant log excerpt:


2026-06-14 14:47:06 [info] Failed to set title bar overlay, this is probably expected
2026-06-14 14:47:10 [info] Failed to set title bar overlay, this is probably expected
2026-06-14 14:47:20 [info] Failed to set title bar overlay, this is probably expected
2026-06-14 14:47:22 [info] Failed to set title bar overlay, this is probably expected
2026-06-14 14:48:37 [warn] [event-loop-stall] main process blocked for 853ms (total 27, cumulative 26097ms, rss 362MB)
2026-06-14 14:48:38 [warn] [event-loop-stall] main process blocked for 726ms (total 28, cumulative 26823ms, rss 313MB)
2026-06-14 14:48:41 [warn] [event-loop-stall] main process blocked for 1999ms (total 29, cumulative 28822ms, rss 312MB)
2026-06-14 14:51:11 [info] Failed to set title bar overlay, this is probably expected
2026-06-14 14:51:11 [info] Failed to set title bar overlay, this is probably expected
2026-06-14 14:51:25 [info] Failed to set title bar overlay, this is probably expected
2026-06-14 14:51:25 [info] Failed to set title bar overlay, this is probably expected

Steps to Reproduce

1. Launch Claude Desktop (Store/MSIX install on Windows 11)
2. Main window opens blank — no content renders
3. Window remains blank indefinitely
4. Pressing Ctrl+Alt+Space → typing anything → waiting for response triggers a repaint and the UI appears

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.11847.5

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Environment

• App version: 1.11847.5
• OS: Windows 11
• Install type: Store-style MSIX package — installed via Anthropic's direct download but packaged as WindowsApps/MSIX
• Install path: C:\Program Files\WindowsApps\Claude_1.11847.5.0_x64__pzs8sxrjxfjjc
• Account type: Personal Pro
• Display: LG HDR 4K, 2560×1440, 150% DPI scaling