[BUG] .py file downloads fail with "Unable to open file" (other file types work fine)

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?

Environment:

• OS: Windows 11 Pro
• App: Claude Desktop / Cowork
• App version: [fill in — Settings → General or Help → About]
• Antivirus/security: Windows Defender only (Controlled Folder Access: off;

Protection history: no relevant entries). Acronis was suspected but is not
installed on this system.

Description:
Downloading a .py file from a Claude chat consistently fails with an
"Unable to open file." toast at the bottom of the Claude window. Other file
types (tested: .wl, .txt, .zip) download successfully to the default
Downloads folder with no issue.

Steps to reproduce:

1. In a Claude chat, have Claude create/attach a .py file (tested with a

simple "print("Hello, World!")" script).

1. Click the "v" (chevron) on the file card.
2. Select "Download".

What Should Happen?

Expected: File saves to the default Downloads directory.
Actual: Toast reads "Unable to open file." No file — not even a temporary
or partial one — ever appears in the Downloads directory.

Error Messages/Logs

Description:
Downloading a .py file from a Claude chat consistently fails with an 
"Unable to open file." toast at the bottom of the Claude window. Other file 
types (tested: .wl, .txt, .zip) download successfully to the default 
Downloads folder with no issue.

Steps to Reproduce

Steps to reproduce:

1. In a Claude chat, have Claude create/attach a .py file (tested with a

simple "print("Hello, World!")" script).

1. Click the "v" (chevron) on the file card.
2. Select "Download".

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

• App version: 1.30096.1.0 (installed/updated 8/13/2026)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

Expected: File saves to the default Downloads directory.
Actual: Toast reads "Unable to open file." No file — not even a temporary
or partial one — ever appears in the Downloads directory.

Additional testing performed:

• Selecting "Download and open" instead of "Download" produces the same

failure.

• Double-clicking the file card does NOT attempt a download at all — it

opens the file's contents in Claude's side preview panel, where the code
is viewable and copyable. This works correctly.

• The identical "Hello World" content, delivered as .txt and as .zip

(containing the same .py file), downloads successfully with no error.

• Windows Defender Controlled Folder Access is off; Protection history

shows nothing relevant around the failed attempts — ruled out as cause.

• No temp/partial/zero-byte file ever appears during a failed .py download,

suggesting the failure happens client-side in the app before any file
write is attempted, rather than being blocked by Windows or security
software.

Workaround: Wrapping the .py file in a .zip before downloading succeeds.
The code can also be retrieved via double-click → copy from the preview
panel.

You can drop that straight into a new issue at github.com/anthropics/claude-code/issues, or use it as the details behind an in-app thumbs-down if you'd rather skip GitHub entirely.