[BUG] Claude Desktop persistent blank/white screen on Windows — Cowork unusable, multiple reinstalls have no effect

Found 3 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/50875
2. https://github.com/anthropics/claude-code/issues/44558
3. https://github.com/anthropics/claude-code/issues/28304

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🤖 Generated with Claude Code

+1

This gets weird. I erased every instance of Claude in the Task manager. Cleared the cache for all time. Web Claude disappeared. I shut down the computer and had a beer. Now I turned it back on, went to Claude.ai and downloaded Claude Desktop. When I installed it Web Claude came back. Now when I click the black icon in the system tray I get the dialogue bubble but no screen. And there are 10 instances of Claude in the task manager. How long will it take Anthropic to get a fix? I am okay with continuing to work with Web Claude, but I really want to work with cowork plugins.
This is the fifth time I have downloaded and installed Claude Desktop
In summary:
Missing %LocalAppData%\AnthropicClaude folder
10 Claude processes in Task Manager but no window rendering
%AppData%\Claude exists but only contains claude-code
Windows version 11 running on a Geekom Air12 Intel processors
A full uninstall, cache clear, reboot, and reinstall didn't resolve it

Exactly the same for me. I have previously had Claude working fine but recent updates and bugs brought this issue to my attention so I tried to reinstall from scratch with no other programs ( apart from background apps running and have had the same experience as everyone else. tried multiple ureinstalls, cleared cache etc

If you are using a custom DNS, check to make sure it isn't blocking Claude. I had the same issue, removed my custom DNS and the issue stopped for desktop version and the browser version.

+1

Same here. Definitely not running a custom DNS. Glad I'm paying Anthropic $$$ for this.

I am experiencing the exact same issue on Windows 11. Blank white screen, Cowork unusable, no app data folders created, multiple reinstalls have not helped. I am a paying customer and have been unable to access Cowork for multiple days. Please fix this urgently.

Same Issue — Windows MSIX, White Screen on Every Launch (ERR_QUIC_PROTOCOL_ERROR)

Environment

• OS: Windows (x64)
• App Version: Claude Desktop 1.12603.1 (MSIX)
• Install Source: https://claude.com/download (official)
• Package: Claude_pzs8sxrjxfjjc
• Developer Mode: ON (AllowDevelopmentWithoutDevLicense = 1)

Symptoms

• White/blank screen immediately on every launch
• App window renders but content area is entirely white
• No user interaction possible
• Reproduced on a second PC with a different network environment
• Web version (claude.ai) works normally in browser

Root Cause (from logs)

Analysis of main.log identified the following error sequence:

2026-06-12 15:56:05 [info] Failed to load URL: https://claude.ai/
  { errorCode: -356, errorDescription: 'ERR_QUIC_PROTOCOL_ERROR' }
2026-06-12 15:56:05 [info] Error page detected: { href: 'chrome-error://chromewebdata/' }
2026-06-12 15:56:05 [info] Redirecting to claude.ai
2026-06-12 15:56:08 [warn] [LocalSessionManager] Cannot initialize sessions: accountId=null, orgId=null
2026-06-12 15:56:08 [info] [account] Account details not yet available, waiting for IPC...
2026-06-12 15:56:49 [warn] [buddy-ble] mainView not ready: Timed out waiting for mainView to become ready

The Electron/Chromium engine fails to load claude.ai via QUIC (HTTP/3 over UDP 443), which cascades into account session failure and a permanent white screen timeout.

Troubleshooting attempted (all failed)

| # | Action | Result |
|---|--------|--------|
| 1 | GPU/Shader cache deletion | No improvement |
| 2 | Full uninstall + residual folder removal (%LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc) | No improvement |
| 3 | Clean reinstall from official installer | No improvement |
| 4 | Developer Mode verification | Confirmed ON |
| 5 | MSIX package repair | No improvement |
| 6 | Full LocalCache deletion | No improvement |
| 7 | QUIC disabled via registry (HKLM/HKCU QuicAllowed=0) | No improvement |
| 8 | QUIC disabled via Chromium policy | No improvement |
| 9 | electron-flags.cfg with --disable-quic | Ignored by MSIX build |
| 10 | UDP 443 firewall block for Claude.exe | No improvement |
| 11 | VPN/Proxy/Antivirus ruled out | Not the cause |
| 12 | TCP connectivity verified | TcpTestSucceeded: True for claude.ai:443 |
| 13 | Reproduced on second PC, different network | Confirms app-side bug |

Key finding: electron-flags.cfg (with --disable-quic) is not respected by the MSIX package distribution, making client-side QUIC workarounds ineffective.

Requested fix

• Automatic fallback from QUIC to TLS/TCP when ERR_QUIC_PROTOCOL_ERROR is encountered
• User-visible error/retry instead of silent white screen on page load failure
• Investigate why electron-flags.cfg is not respected in the MSIX build

Cowork is completely inaccessible as a result. Happy to provide additional logs if helpful.

Update: Issue Resolved (2026-06-23)

The app started working again today without any changes on my end — the login screen appeared normally on launch.

This suggests the fix was either a server-side change by Anthropic or an automatic app update. Leaving this here in case it helps others experiencing the same ERR_QUIC_PROTOCOL_ERROR white screen issue.

Additional info: OS is Windows Home edition.

Following this, having the same issue and nothing works... Thanks.

Same issue.

Managed to get Claude functional again by doing a full reinstall/repair from the Windows Add/Remove programs prompt. This deleted all my cowork projects and chat history.

I was able to recover everything from a Windows backup, but that also brough back the blank screen issue, and I've been completely unable to use Claude since.

Same problem. It happened after I updated my Nvidia drivers.

I used Claude in powershell mode to fix the problem.

Try the following:

1. Antivirus/Security — Check if you have Kaspersky, ESET, Norton, or similar. Many block QUIC. Disable it temporarily and test.

1. Router — Access the router's control panel and check if UDP on port 443 is blocked (some routers have "QoS" or "SPI Firewall" that blocks QUIC).

1. VPN — If you use a VPN, disable it and test.

1. Force HTTP/2 — In the Windows Firewall, it intentionally blocks UDP 443 to force Electron to drop to TCP/HTTP2.

Hope this helps.

Platform: Claude Desktop (Windows)

Claude Desktop Version: Latest

Operating System: Windows 11 Home 64-bit (Build 26200)

GPU: NVIDIA GeForce RTX 5070 (Driver 32.0.16.1047, dated 5/19/2026)

Monitor setup: Desktop PC (stationary) with external monitor
Problem:

Claude Desktop opens to a completely blank/white screen on every launch. The window frame appears with minimize/maximize/close buttons, but no content ever renders.
What I tried:

Killed all Claude processes via Task Manager and relaunched — no effect
Deleted %APPDATA%\Claude cache folders (Cache, Code Cache, GPUCache) — no effect
Added --disable-gpu launch flag — no effect
Full clean reinstall (uninstalled, deleted all AppData folders, rebooted, reinstalled) — no effect
Note: %LocalAppData%\AnthropicClaude folder was not created after reinstall, suggesting the app is failing to initialise properly

Expected behaviour:

App should launch and display the UI normally.

I hit a related Windows Desktop failure mode where the browser could open https://claude.ai, but Claude Desktop either failed to render / could not connect through the same proxy path.

I published an unofficial workaround here:

https://github.com/king-sheol/claude-desktop-windows-proxy-launcher

Latest release ZIP:
https://github.com/king-sheol/claude-desktop-windows-proxy-launcher/releases/latest

Scope / caveats:

• Unofficial, not affiliated with Anthropic.
• Does not modify, patch, decompile, or redistribute Anthropic software.
• Does not delete Claude data, projects, sessions, plugins, or settings.
• Does not replace the official Claude shortcut.
• It is not a universal Cowork VM networking fix.

What it does:

• Launches the existing Claude.exe with explicit Chromium/Electron flags such as --proxy-server, --disable-quic, and GPU-workaround flags.
• Also sets proxy environment variables for child processes.
• Searches for both MSIX/AppX and Win32/Squirrel install locations.
• Includes a dry-run mode and an optional shortcut installer that creates a separate Claude Desktop Proxy Launcher shortcut.

This is most relevant for cases where claude.ai works in the browser, but the main Claude Desktop Electron UI is blank, white-screened, or shows "Could not connect to Claude". It may also help users whose MSIX build ignores electron-flags.cfg, since the flags are passed at process launch instead.

Again, this is a workaround, not a replacement for an upstream fix. Ideally Claude Desktop should expose supported proxy / network settings and handle QUIC/proxy failures with a visible retry/error path instead of a permanent blank screen.

I realized that my computer set time was out of sync, changed it from manual to auto, and reopened claude and it fixed the issue.

For me deleting %AppData%\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\Local Storage and GPUCache fixed the issue after trying everything else

I don't think this is going to be useful for anyone, but after restarting my PC for weeks, and cleaning and relaunching the Claude app, today (17/07/2026) it worked again. Nothing specific I can share here... I just deleted everything installed, restarted, and did a clean install (several times).

Adding a data point from a Windows 11 Pro build 26200 machine, because it isolates where the cowork build dies.

Symptom: cowork Desktop (MSIX, Claude_1.24012.9.0_x64__pzs8sxrjxfjjc) launches and exits within ~8s with no window. ...\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\logs\main.log is never (re)written on the failing launches — the Electron main process dies before it logs anything.

Verified on a clean, fully-intact install:

• Files intact: 2166 files, 0 zero-byte, claude.exe 232 MB, resources\app.asar 38 MB, valid Anthropic, PBC Authenticode signature. (An earlier attempt did have ~74 zero-byte files from an interrupted download; a clean reinstall fixed that, but the launch failure persists even with all files intact.)
• Get-AppxPackage still reports Status: Modified, NeedsRemediation on the clean install.
• Microsoft-Windows-AppModel-Runtime/Admin shows the app does launch at the OS level (Event 201 [LaunchProcess], PID assigned; Events 210/211 = connected to the AppX host), then the host is torn down (Event 217) ~8s later.
• No WER crash — Application log has no 1000/1001/1026 for claude.exe or cowork-svc.exe.
• CoworkVMService is healthy. C:\ProgramData\Claude\Logs\cowork-service.log shows, on every launch: vmcompute.dll / computecore.dll loaded, HCS ready, HCN init from computenetwork.dll + EnumerateNetworks OK, signature verification OK, named pipe \\.\pipe\cowork-vm-service listening, Service ready. It then sits at Waiting for configuration from app via 'configure' method... and the app never sends configure before it exits.

So on this build the VM/HCS side is fine — the Electron main process exits very early (before writing main.log and before configuring cowork), which then tears the AppX host down. NTFS compression is off on C:, and there is no active third-party AV interfering.

Working workaround on the same machine: the non-cowork standalone build launches and runs fine — winget install Anthropic.Claude (Squirrel build, installs to %LOCALAPPDATA%\AnthropicClaude, ships no CoworkVMService). You lose cowork, but you get a usable desktop app on build 26200.