[BUG] Claude Desktop on Windows loops on "A new version of Claude is available" with error 1XAF0WC after update

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?

After Claude Desktop updated to version 1.24012.9 on Windows 11, opening the app displayed “A new version of Claude is available” with error code 1XAF0WC.

Clicking “Reload” or “Go to home” returned to the same error page. Completely closing Claude, verifying that no claude.exe processes remained, and performing a cold restart reproduced the same error.

The application recovered only after Claude was fully closed and the following Electron cache directories were renamed so that the app could recreate them:

• %APPDATA%\Claude\Cache
• %APPDATA%\Claude\Code Cache
• %APPDATA%\Claude\GPUCache

No account data, configuration, local storage, or session files were removed.

What Should Happen?

Claude Desktop should load the current interface normally after an update.

If a cached SPA entrypoint or JavaScript chunk is stale or cannot be loaded, the app should invalidate or bypass the affected cache and recover automatically instead of repeatedly displaying the fatal update screen.

The user should not need to manually rename or delete Electron cache directories.

Error Messages/Logs

2026-07-28 14:28:22 [warn] [spa] chunk preload failed; running diagnostics, then reloading TypeError: Failed to fetch dynamically imported module: https://assets-proxy.anthropic.com/claude-ai/v2/assets/v1/cf52a4cc1-DaHTBzOx.js

2026-07-28 14:28:26 [error] TypeError: Failed to fetch dynamically imported module: https://assets-proxy.anthropic.com/claude-ai/v2/assets/v1/cd377abb5-CyivASTZ.js

2026-07-28 14:28:26 [error] [BOOTSTRAP] Fatal error boundary triggered {"errorMessage":"Failed to fetch dynamically imported module: https://assets-proxy.anthropic.com/claude-ai/v2/assets/v1/cd377abb5-CyivASTZ.js","errorCode":"1XAF0WC","url":"/epitaxy"}

Steps to Reproduce

1. Use Claude Desktop on Windows 11 with an existing user profile and Electron cache from a previous version.
2. Update Claude Desktop to version 1.24012.9.
3. Launch Claude Desktop.
4. The app displays “A new version of Claude is available” with error code 1XAF0WC.
5. Click “Reload”.
6. The same error screen appears again.
7. Fully terminate all claude.exe processes and launch the app again.
8. The error is reproduced and the log records a failed dynamic import on the /epitaxy route.
9. Fully close Claude again and rename %APPDATA%\Claude\Cache, Code Cache, and GPUCache.
10. Launch Claude Desktop. The cache directories are recreated and the application loads normally without a new 1XAF0WC event.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.220 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

Environment:

• Claude Desktop: 1.24012.9 (Windows MSIX package 1.24012.9.0)
• Electron: 42.7.0
• Claude Code: 2.1.220
• Operating system: Windows 11 Pro 25H2, build 26200.8875
• Windows package status: OK

Diagnostics performed:

• A full cold restart, after verifying that zero claude.exe processes remained, still reproduced the error.
• Both JavaScript assets named in the log were tested independently from the same machine and returned HTTP 200 with a JavaScript content type.
• No user proxy was configured.
• Windows Firewall had enabled outbound allow rules for Claude.

• With Claude fully closed, renaming only Cache, Code Cache, and GPUCache caused the application to recreate them and resolved the startup loop.
• No new 1XAF0WC event was logged after the clean cache regeneration.
• Configuration, IndexedDB, Local Storage, Session Storage, Network data, and local Claude Code sessions were not modified.

Possibly related reports:

• https://github.com/anthropics/claude-code/issues/64960 - same error code and /epitaxy dynamic-import failure on macOS; closed as stale.
• https://github.com/anthropics/claude-code/issues/76430 - same error code appeared during an update, but the primary report concerns missing sidebar sessions.

<img width="735" height="511" alt="Image" src="https://github.com/user-attachments/assets/5dcdb723-ddfa-4ebc-9281-c85868373574" />