[BUG] Claude Desktop 2.7032.0 (Windows) fails to start after auto-update — registry error 1021 (stable subkey under volatile parent), Reset/Repair/reinstall do not recover

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?

Summary
Claude Desktop auto-updated overnight from 2.2553.13 to 2.7032.0 and has not started since. It aborts immediately with a Windows registry error 1021 (ERROR_CHILD_MUST_BE_VOLATILE: "A stable subkey cannot be created under a volatile parent key"). Repair, Reset, reboot and a full uninstall/reinstall do not recover it.
Environment

• Claude Desktop 2.7032.0 (auto-updated 2026-09-23 at 01:34 local time; previous version 2.2553.13 worked fine on 2026-09-22)
• Windows [11 / 10], build [z. B. 26200.9445 — steht unter Einstellungen > System > Info]
• Install type: [Microsoft Store / MSIX | Download von claude.ai]
• Last Windows cumulative update: 2026-09-17 (no issue until the Claude update)
• Claude Code CLI works on the same machine (claude remote-control is my current workaround)

Steps to reproduce

1. Have Claude Desktop 2.2553.13 installed and working.
2. Let the app auto-update to 2.7032.0 overnight.
3. Launch Claude Desktop.

Expected
App starts.
Actual
App exits immediately. Windows reports registry error 1021 ("Ein dauerhafter Unterschlüssel kann nicht unter einem temporären übergeordneten Schlüssel erstellt werden" / "A stable subkey cannot be created under a volatile parent key").
What I tried (none helped)

• Reboot
• Settings > Apps > Claude > Repair
• Settings > Apps > Claude > Reset
• Full uninstall and reinstall of the current installer

Notes

• Support ticket already open: 215476063369580
• Related but different error codes: #94241 (0x80070002 after 1.52386.x updates, only Reset recovers). In my case Reset does not recover.
• Happy to provide logs from %LOCALAPPDATA%\Claude\Logs and the AppModel-Runtime event log on request.

What Should Happen?

App starts

Error Messages/Logs

Windows registry error 1021 (ERROR_CHILD_MUST_BE_VOLATILE) on launch:
"Ein dauerhafter Unterschlüssel kann nicht unter einem temporären übergeordneten Schlüssel erstellt werden"
("A stable subkey cannot be created under a volatile parent key")

The app exits immediately; no window appears.
Logs from %LOCALAPPDATA%\Claude\Logs and the AppModel-Runtime event log available on request.

Steps to Reproduce

1. Have Claude Desktop 2.2553.13 installed and working on Windows (worked fine on 2026-09-22).
2. Let the app auto-update overnight to 2.7032.0 (happened 2026-09-23 at 01:34 local time).
3. Launch Claude Desktop.

Result: the app aborts immediately with registry error 1021 (see Error Messages).

Environment:

• Claude Desktop 2.7032.0, previous version 2.2553.13
• Windows [11 / 10], build [Einstellungen > System > Info]
• Install type: [Microsoft Store / MSIX | download from claude.ai]
• Last Windows cumulative update: 2026-09-17, no issue until the Claude update
• Claude Code CLI works on the same machine ("claude remote-control" is my current workaround)

What I tried, none helped:

• Reboot
• Settings > Apps > Claude > Repair
• Settings > Apps > Claude > Reset
• Full uninstall and reinstall with the current installer

Notes:

• Support ticket already open: 215476063369580
• Related but different: #94241 (0x80070002 after 1.52386.x updates, Reset recovers there). In my case Reset does not recover.
• The suggested duplicate #66214 is a different, older failure (app-1.11187.4) and does not mention error 1021.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.2553.13 (Claude Desktop)

Claude Code Version

2.1.280 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_