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🧩 SetupDiag (Windows Setup Failure Diagnostic Tool)
Category: Installation & Media
Author: jmarket (PCHF Founder)
Verified by: PCHF Staff • October 2025
Overview
SetupDiag is Microsoft’s official diagnostic utility designed to analyze Windows Setup and upgrade logs to determine why an installation or feature update failed.
It scans log files, detects known error patterns, and generates a detailed report explaining the cause of failure in plain language.
SetupDiag supports both Windows 10 and Windows 11 (including the latest 25H2 build) and can be run locally or offline from recovery environments.
For IT professionals and advanced users, SetupDiag provides quick insights into issues such as driver incompatibilities, insufficient disk space, or update-related errors — helping identify the root cause of upgrade failures far more efficiently than manual log inspection.
Key Features
- Automated Log Analysis: Scans setup logs for known error signatures and generates a summary report.
- Comprehensive Error Detection: Recognizes hundreds of failure scenarios, including driver, compatibility, and update-related issues.
- Offline and Live Support: Can be executed from within Windows or externally on a mounted system.
- Plain-Language Explanations: Converts complex setup logs into readable summaries for technicians.
- Continuous Updates: Updated frequently by Microsoft to support new Windows builds and error codes.
System Requirements
- Operating System: Windows 10 or Windows 11 (any edition)
- Architecture: 64-bit recommended
- Privileges: Administrator rights required
- Log Path: Access to
C:\$WINDOWS.~BT\Sources\Panther(or copied logs)
How to Use SetupDiag
- Visit the official Microsoft SetupDiag documentation page.
- Download the latest SetupDiag.exe file.
- Copy the tool to the system where the installation or upgrade failed.
- Run
SetupDiag.exefrom an elevated Command Prompt, or double-click to launch the graphical mode. - Wait for analysis to complete. A log file named SetupDiagResults.log will be created in the same directory.
Example Command
SetupDiag.exe /Output:C:\Temp\SetupDiagResults.log
This command specifies an output location for the diagnostic summary file.
Verifying Integrity
Microsoft publishes SHA-256 checksum values for SetupDiag when applicable.
You can verify file integrity after download using PowerShell or Command Prompt:
CertUtil -hashfile SetupDiag.exe SHA256
Compare the resulting hash with the one listed on the official Microsoft Learn page.
Interpreting Results
SetupDiag summarizes its findings in a human-readable format.
Typical entries include the error code, associated driver or update, and a brief explanation.
Common examples include:
| Error Code | Meaning | Typical Cause |
|---|---|---|
| 0xC1900101 | Driver error | Outdated or incompatible drivers (e.g., chipset, network, or storage) |
| 0x8007042B | Unexpected process termination | Background process interference or insufficient memory |
| 0xC1900208 | Compatibility hold | Blocked software detected that prevents upgrade |
| 0x8007001F | I/O device error | Disk or hardware malfunction during upgrade |
Advanced Usage
- Use
/LogsPathto analyze logs stored in a different directory or on another partition. - Combine with
/Format:CSVto generate structured output for automation or reporting. - Run from Windows Recovery Environment (WinRE) to diagnose failed upgrades on offline disks.
Notes
- SetupDiag is best used for diagnosing upgrade failures such as
0xC1900101,0x8007042B, or0x8007001F. - The tool does not modify system files and can safely be run multiple times.
- Compatible with all modern Windows 11 releases, including 25H2 (Build 26100.***).
Policy
Only official Microsoft download links are allowed.
Redistributing or hosting the SetupDiag executable outside of Microsoft’s servers is not permitted.
This ensures that users always receive the authentic, unmodified binary.
Download
Official Microsoft SetupDiag Documentation & Download Page
Technical Information
- Publisher: Microsoft Corporation
- Version: 1.6.0.0 (Supports Windows 10 and Windows 11 including 25H2)
- Release Date: October 2025
- License: Freeware (Microsoft Official Utility)
Related Articles
- Windows 11 Media Creation Tool (Official Microsoft Utility)
- Windows 11 ISO (Official Microsoft Download)
- DISM — Complete Guide for Windows 11 25H2
All content © 2025 PC Help Forum.
SetupDiag is developed and maintained by Microsoft Corporation.
All download links provided lead directly to Microsoft’s official documentation and CDN sources. Redistribution of binaries is not permitted.