[BUG] Error when trying to install Claude Desktop

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?

Please share this log with us.
2026/06/04 10:45:03.775602 Elevated process exited with code 1
2026/06/04 10:45:03.775602 Elevation failed: elevated installer exited with code 1
2026/06/04 10:45:03.775602 ERROR dialog (with log path): Administrator access is required to install Claude with full features. You can try again or install without Cowork.
2026/06/04 10:52:46.966066 Log file: C:\Users\felix\AppData\Local\Temp\ClaudeSetup.log
2026/06/04 10:52:46.967507 === Claude Setup deee0a79e9070caed69480a2c8d2e09f895512c4 started ===
2026/06/04 10:52:46.970445 AllowDevelopmentWithoutDevLicense found with value: 1
2026/06/04 10:52:46.970445 Windows edition: Professional
2026/06/04 10:52:46.974122 Windows version: 10.0.26200
2026/06/04 10:52:46.974122 Native arch: x64
2026/06/04 10:52:46.975249 Elevation type: Full
2026/06/04 10:52:46.975249 Is elevated: true
2026/06/04 10:52:46.975249 Sideloading enabled: true
2026/06/04 10:52:46.975249 S Mode: false
2026/06/04 10:52:46.975249 Conflicting service: false
2026/06/04 10:52:46.975249 Running in non-elevated context
2026/06/04 10:52:46.975249 User can elevate — installing MSIX directly
2026/06/04 10:52:47.049940 Splash: 400x300, 8 frame(s), animated=true
2026/06/04 10:52:47.051948 System DPI: 144 (scale: 150%)
2026/06/04 10:52:47.215188 MSIX URL: https://api.anthropic.com/api/desktop/win32/x64/msix/latest/redirect
2026/06/04 10:52:47.216708 Downloading MSIX to C:\Users\felix\AppData\Local\Temp\Claude-3457715789.msix
2026/06/04 10:52:47.274260 proxy: WinHttpGetProxyForUrl("https://api.anthropic.com/api/desktop/win32/x64/msix/latest/redirect"): winapi error #12180
2026/06/04 10:52:47.594505 proxy: WinHttpGetProxyForUrl("https://downloads.claude.ai/releases/win32/x64/1.10628.2/Claude-deee0a79e9070caed69480a2c8d2e09f895512c4.msix"): winapi error #12180
2026/06/04 10:52:48.453404 Download progress: 10% (22101856 / 220910408 bytes)
2026/06/04 10:52:48.839442 Download progress: 20% (44187344 / 220910408 bytes)
2026/06/04 10:52:49.230611 Download progress: 30% (66305552 / 220910408 bytes)
2026/06/04 10:52:49.544357 Download progress: 40% (88374640 / 220910408 bytes)
2026/06/04 10:52:49.863100 Download progress: 50% (110460096 / 220910408 bytes)
2026/06/04 10:52:50.192821 Download progress: 60% (132562000 / 220910408 bytes)
2026/06/04 10:52:50.542957 Download progress: 70% (154647472 / 220910408 bytes)
2026/06/04 10:52:50.924874 Download progress: 80% (176749248 / 220910408 bytes)
2026/06/04 10:52:51.237562 Download progress: 90% (198851104 / 220910408 bytes)
2026/06/04 10:52:51.530490 Download progress: 100% (220910408 / 220910408 bytes)
2026/06/04 10:52:51.532089 Download complete: 220910408 bytes, SHA256: b79f9dd744797f8377069a232825172964670ea39e659983d516242e598c833a
2026/06/04 10:52:51.533231 Download complete
2026/06/04 10:52:51.566342 Self-elevating: C:\Users\felix\Downloads\Claude Setup (1).exe --elevated --msix-path "C:\Users\felix\AppData\Local\Temp\Claude-3457715789.msix" --log-path "C:\Users\felix\AppData\Local\Temp\ClaudeSetup.log"
2026/06/04 10:52:51.807823 Waiting for elevated process to complete...
2026/06/04 10:52:51.830835 Log file: C:\Users\felix\AppData\Local\Temp\ClaudeSetup.log
2026/06/04 10:52:51.831893 === Claude Setup deee0a79e9070caed69480a2c8d2e09f895512c4 started ===
2026/06/04 10:52:51.833670 AllowDevelopmentWithoutDevLicense found with value: 1
2026/06/04 10:52:51.833670 Windows edition: Professional
2026/06/04 10:52:51.834930 Windows version: 10.0.26200
2026/06/04 10:52:51.834930 Native arch: x64
2026/06/04 10:52:51.834930 Elevation type: Full
2026/06/04 10:52:51.834930 Is elevated: true
2026/06/04 10:52:51.834930 Sideloading enabled: true
2026/06/04 10:52:51.834930 S Mode: false
2026/06/04 10:52:51.834930 Conflicting service: false
2026/06/04 10:52:51.834930 Running in elevated context
2026/06/04 10:52:51.835676 Installing MSIX from C:\Users\felix\AppData\Local\Temp\Claude-3457715789.msix (all-users: false)
2026/06/04 10:52:51.889190 Splash: 400x300, 8 frame(s), animated=true
2026/06/04 10:52:51.889190 System DPI: 144 (scale: 150%)
2026/06/04 10:52:51.957000 Verifying Authenticode signature on C:\Users\felix\AppData\Local\Temp\Claude-3457715789.msix
2026/06/04 10:52:56.113471 WinVerifyTrust: MSIX signature is valid
2026/06/04 10:52:58.148998 Signature verified: MSIX signer matches bootstrapper
2026/06/04 10:52:58.149517 Squirrel process prefix: c:\users\felix\appdata\local\anthropicclaude\
2026/06/04 10:52:58.149517 Checking for running Squirrel Claude processes...
2026/06/04 10:52:58.170168 No Squirrel Claude processes found
2026/06/04 10:52:58.170168 Checking for existing Claude MSIX packages...
2026/06/04 10:52:58.349900 Installing MSIX: C:\Users\felix\AppData\Local\Temp\Claude-3457715789.msix
2026/06/04 10:52:58.357398 Extracted family name from MSIX manifest: Claude_pzs8sxrjxfjjc
2026/06/04 10:52:58.357398 Standard install (not split-account), using AddPackage
2026/06/04 10:52:58.357398 Installing via AddPackage (current-user)...
2026/06/04 10:52:59.874136 MSIX installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CFF
2026/06/04 10:52:59.874136 ERROR dialog (opening log): Installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CFF

Please share this log with us.
2026/06/04 10:53:04.558910 Elevated process exited with code 1
2026/06/04 10:53:04.558910 Elevation failed: elevated installer exited with code 1
2026/06/04 10:53:04.558910 ERROR dialog (with log path): Administrator access is required to install Claude with full features. You can try again or install without Cowork.

What Should Happen?

Allow me to install Claude Desktop on my Laptop

Error Messages/Logs

Steps to Reproduce

Aquí está el texto listo para pegar en el issue de GitHub:

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Steps to Reproduce

1. Download Claude Desktop installer from claude.com/download (Windows x64)
2. Right-click installer → Properties → Unblock → Apply → OK
3. Right-click installer → Run as administrator
4. Installer downloads MSIX successfully and verifies Authenticode signature
5. Installation fails at AddPackage step with HRESULT 0x80073CFF

Environment

• OS: Windows 11 Pro, build 10.0.26200, x64
• Account type: Administrator (Microsoft account)
• Sideloading enabled: true
• S Mode: false
• Developer Mode: toggled grayed out in Settings (UI unresponsive)
• Registry keys manually set via PowerShell:
• AllowAllTrustedApps = 1
• AllowDevelopmentWithoutDevLicense = 1
• All attempts fail consistently across multiple installer versions and fresh downloads

Expected behavior: Claude Desktop installs successfully.

Actual behavior: MSIX installation failed: AddPackage failed with HRESULT 0x80073CFF — persists even with registry keys set, full elevation confirmed, and valid MSIX signature verified.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Desktop

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_