Fix SQL Server Error 0x80070643

Understanding Error 0x80070643

This error code translates to "ERROR_INSTALL_FAILURE" in Windows system codes, indicating a fatal failure during the installation or update process.

Where This Error Appears:

• Windows Update: When installing SQL Server security updates via Windows Update or WSUS
• SQL Server Setup: During new SQL Server installation or cumulative updates
• Microsoft Update Catalog: When manually installing downloaded .msu update packages
• .NET Framework: During .NET installation required by SQL Server

Affected SQL Server Versions:

• SQL Server 2022, 2019, 2017, 2016
• SQL Server 2014, 2012, 2008 R2
• SQL Server Express editions
• Azure Data Studio and SSMS (SQL Server Management Studio) updates

Error Variants:

The error may appear with slightly different messages:

• "Windows Update error 0x80070643"
• "SQL Server setup failed with error code 0x80070643"
• "Fatal error during installation. Error code: 0x80070643"
• ".NET Framework update failed: 0x80070643"

Method 1: Restart Windows Installer Service

The Windows Installer service (msiserver) handles all .msi package installations, including SQL Server updates. If stopped or corrupted, installations fail with 0x80070643.

1. Press Windows + R to open Run dialog
2. Type: services.msc
3. Press Enter to open Services console
4. Scroll down to find Windows Installer
5. Check current Status (should be blank when not actively installing)
6. Right-click Windows Installer
7. Select Restart (if status shows "Running")
8. If "Restart" is grayed out or service is stopped:
   • Right-click and select Properties
   • Set Startup type to Manual
   • Click Start button
   • Click Apply then OK
9. Close Services console
10. Restart your computer
11. After reboot, retry SQL Server update installation

Reset Windows Installer via Command Prompt:

1. Open Command Prompt as Administrator
2. Stop the service: net stop msiserver
3. Wait 10 seconds
4. Start the service: net start msiserver
5. If start fails, re-register Windows Installer:
6. Run: msiexec /unregister
7. Wait 5 seconds
8. Run: msiexec /regserver
9. Restart computer
10. Try SQL update again

Why this works: Windows Installer can become unresponsive or enter an error state after failed installations. Restarting clears the service state and re-registers the installer engine, resolving transient errors that block subsequent installations.

Method 2: Repair .NET Framework

SQL Server relies heavily on .NET Framework. Corrupted .NET components cause installation failures with error 0x80070643. Microsoft provides an official repair tool.

1. Download Microsoft .NET Framework Repair Tool from: Microsoft Download Center
2. Run NetFxRepairTool.exe as Administrator
3. Accept license terms
4. The tool automatically detects .NET issues
5. Click Next if problems detected
6. Tool applies repairs (takes 5-15 minutes)
7. Review the log for "Repair succeeded"
8. Click Finish
9. Restart your computer
10. Retry SQL Server update

Alternative: Repair .NET Framework Manually via DISM:

1. Open Command Prompt as Administrator
2. Check .NET Framework health:
3. Run: DISM /Online /Cleanup-Image /ScanHealth
4. If corruption detected, repair:
5. Run: DISM /Online /Cleanup-Image /RestoreHealth
6. Wait for completion (10-30 minutes)
7. After DISM completes, run System File Checker:
8. Run: sfc /scannow
9. Wait for 100% completion
10. Restart computer

Reinstall .NET Framework (if repair fails):

1. Press Windows + I → Apps → Optional features
2. Click View features
3. Search for ".NET Framework"
4. Check .NET Framework 3.5 and .NET Framework 4.8
5. Click Install
6. Wait for installation (may require restart)
7. Alternatively, download latest .NET from Microsoft .NET site

Why this matters: SQL Server 2016 and later require .NET Framework 4.6+ for setup and updates. Corrupted .NET assemblies prevent installer DLL loading, triggering 0x80070643.

Method 3: Clear Windows Installer Cache

Corrupted cached installer files cause repeated installation failures. Clearing the cache forces Windows to download fresh update files.

1. Open Command Prompt as Administrator
2. Stop Windows Update service: net stop wuauserv
3. Stop Windows Installer: net stop msiserver
4. Navigate to cache folder: cd %windir%
5. Rename the SoftwareDistribution folder:
6. Run: ren SoftwareDistribution SoftwareDistribution.old
7. Navigate to Windows Installer cache:
8. Run: cd %windir%\Installer
9. Create backup: mkdir C:\Installer_Backup
10. Copy patch files: xcopy *.msp C:\Installer_Backup\ /s
11. Delete cached patch files: del *.msp (use carefully!)
12. Restart services:
13. net start wuauserv
14. net start msiserver
15. Restart computer
16. Run Windows Update to redownload SQL Server update

Safer alternative (recommended for beginners):

1. Download and run Windows Update Troubleshooter:
   • Press Windows + I → System → Troubleshoot → Other troubleshooters
   • Click Run next to "Windows Update"
   • Follow prompts to automatically clear cache and reset update components

Method 4: Run Installation with Full Administrator Permissions

Even administrator accounts can lack sufficient permissions if User Account Control (UAC) or security policies restrict installer access to critical registry keys.

Create Elevated Administrator Account:

1. Open Command Prompt as Administrator
2. Enable built-in Administrator account:
3. Run: net user administrator /active:yes
4. Set password: net user administrator YourStrongPassword123!
5. Log out of current account
6. Log in as Administrator
7. Run SQL Server update installation
8. After successful installation, log back to your regular account
9. Disable Administrator account: net user administrator /active:no

Grant Full Permissions to Registry Keys:

1. Press Windows + R, type regedit, press Enter
2. Navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer
3. Right-click Installer key → Permissions
4. Click Advanced
5. Click Change next to Owner
6. Type your username, click Check Names, then OK
7. Check Replace owner on subcontainers and objects
8. Click OK
9. In Permissions window, click Add
10. Type "SYSTEM", click Check Names, OK
11. Check Full Control
12. Click OK on all windows
13. Restart computer
14. Try SQL update again

Disable UAC Temporarily:

1. Press Windows + R, type UserAccountControlSettings.exe
2. Drag slider to bottom (Never notify)
3. Click OK
4. Restart computer
5. Install SQL Server update
6. Important: Re-enable UAC after installation for security

Why this works: SQL Server installers modify protected registry hives and system folders. Restricted permissions prevent these modifications, causing installation failure. Full administrator access grants necessary rights.

Method 5: Temporarily Disable Antivirus and Firewall

Security software can block SQL Server installer processes, mistaking them for suspicious system modifications, especially when installers write to registry or create services.

1. Disable Windows Defender (Windows 11/10):
   • Press Windows + I → Privacy & security → Windows Security
   • Click Virus & threat protection
   • Click Manage settings
   • Turn off Real-time protection
   • Turn off Cloud-delivered protection
2. Disable third-party antivirus:
   • Right-click antivirus icon in system tray
   • Select Disable, Pause protection, or similar
   • Choose "Until computer is restarted" option
3. Disable Windows Firewall:
   • Press Windows + R, type firewall.cpl
   • Click Turn Windows Defender Firewall on or off
   • Select Turn off Windows Defender Firewall for both Private and Public networks
   • Click OK
4. Run SQL Server update installation
5. Immediately re-enable all security software after installation

Security note: Only disable protection temporarily for installation. Disconnect from internet during this time if possible. Re-enable immediately after completion.

Create Antivirus Exclusions (safer alternative):

1. Add these folders to antivirus exclusions:
   • C:\Program Files\Microsoft SQL Server\
   • C:\Windows\Installer\
   • C:\Windows\Temp\
   • %TEMP% (User temp folder)
2. Add these processes to exclusions:
   • msiexec.exe
   • setup.exe
   • sqlservr.exe
3. Try installation without fully disabling antivirus

Method 6: Check and Free Disk Space

SQL Server updates require significant temporary disk space for unpacking installation files. Insufficient space causes silent failures with error 0x80070643.

1. Check available space:
   • Open This PC in File Explorer
   • Verify C: drive has at least 10 GB free (preferably 20+ GB)
2. Clean temporary files:
   • Press Windows + R, type cleanmgr, press Enter
   • Select C: drive
   • Click OK
   • Check Temporary files, Windows Update Cleanup, System created Windows Error Reporting
   • Click Clean up system files
   • Check Previous Windows installations (if available, saves 10+ GB)
   • Click OK and Delete Files
3. Clear Windows Update cache manually:
   • Navigate to C:\Windows\SoftwareDistribution\Download\
   • Delete all contents (requires admin rights)
4. Clear Temp folders:
   • Delete contents of C:\Windows\Temp\
   • Delete contents of %TEMP% (press Windows + R, type %temp%, delete all)
5. After freeing space, restart computer
6. Retry SQL Server update

Minimum space requirements:

• SQL Server Express: 6 GB free (minimum)
• SQL Server Standard/Enterprise: 10-15 GB free for updates
• Cumulative Updates (CU): 5-8 GB temporary space needed during extraction

Method 7: Review SQL Server Setup Logs

SQL Server generates detailed installation logs that pinpoint exact failure causes. Analyzing these logs reveals specific files, registry keys, or permissions causing 0x80070643.

Locate SQL Server Setup Logs:

1. Navigate to: C:\Program Files\Microsoft SQL Server\[Version]\Setup Bootstrap\Log\
   • Example: C:\Program Files\Microsoft SQL Server\150\Setup Bootstrap\Log\ (SQL 2019)
2. Find the most recent folder (sorted by date/time)
3. Open Summary.txt for overview
4. Open Detail.txt for comprehensive log
5. Search (Ctrl+F) for:
   • "Error"
   • "Failed"
   • "0x80070643"
   • "Exception"
6. Note any file paths, DLL names, or registry keys mentioned near errors

Common Log Errors and Solutions:

Error: "Could not open key: HKEY_LOCAL_MACHINE\SOFTWARE\..."

• Cause: Insufficient registry permissions
• Fix: Use Method 4 to grant full permissions to Installer registry key

Error: "Failed to install MSI package... Return code: 1603"

• Cause: Windows Installer failure
• Fix: Use Method 1 to restart and re-register Windows Installer

Error: "Failed to retrieve data for this request... .NET Framework"

• Cause: .NET Framework corruption
• Fix: Use Method 2 to repair .NET Framework

Error: "There is not enough space on the disk"

• Cause: Low disk space on C: drive or TEMP folder location
• Fix: Use Method 6 to free disk space

Check Windows Update Logs:

1. Open Event Viewer: Press Windows + X, select Event Viewer
2. Navigate to: Windows Logs → System
3. Filter current log for:
   • Source: "Microsoft-Windows-WindowsUpdateClient"
   • Event ID: 20, 24, 25 (installation failures)
4. Review error details for additional clues

Advanced Troubleshooting: Repair SQL Server Installation

If updates repeatedly fail, the existing SQL Server installation may be corrupted. Running a repair can fix underlying issues.

1. Insert SQL Server installation media or mount ISO
2. Run setup.exe as Administrator
3. In SQL Server Installation Center, click Maintenance
4. Click Repair
5. Select the SQL Server instance to repair
6. Click Next through prompts
7. Review repair summary and click Repair
8. Wait for completion (15-45 minutes)
9. After repair finishes, restart computer
10. Try installing cumulative update again

Prevention and Best Practices

• Keep .NET Framework updated independently of SQL Server
• Maintain 20+ GB free space on system drive for updates
• Apply SQL Server updates within maintenance windows to minimize production impact
• Test updates in non-production environment first
• Backup databases before major cumulative updates
• Run Windows Update regularly to prevent component drift between OS and SQL
• Review SQL setup logs after every installation to catch issues early
• Create system restore point before updates for easy rollback
• Exclude SQL Server folders from aggressive antivirus scanning

Frequently Asked Questions

Q: Error 0x80070643 appears only for SQL Server updates, not other Windows updates. Why?

A: SQL Server updates use Windows Installer (.msi packages) and have complex dependencies (.NET Framework, registry configurations, service accounts). Other Windows updates often use different update mechanisms (CBS updates). SQL updates are more sensitive to Windows Installer health, .NET corruption, and permission issues. Fix Windows Installer and .NET using Methods 1-2.

Q: Can I skip this failing SQL Server security update and install a newer one instead?

A: Not recommended. SQL Server cumulative updates are cumulative by name but often have prerequisites. Skipping a failed update may cause later updates to fail as well. Always resolve the 0x80070643 error to install the failing update, then proceed to newer versions. If desperate, try uninstalling SQL instance and performing fresh installation with latest cumulative update integrated.

Q: I repaired .NET Framework but still get 0x80070643. What else could it be?

A: After ruling out .NET, check: (1) Windows Installer service corruption (Method 1), (2) Cached installer files corruption (Method 3), (3) Insufficient permissions (Method 4), (4) Antivirus interference (Method 5). Review SQL setup logs (Method 7) for specific failure points—logs often reveal registry keys or DLL files causing the issue.

Q: Does error 0x80070643 mean my SQL Server databases are corrupted?

A: No. This error indicates an installation/update failure, not database corruption. Your databases remain intact and SQL Server continues functioning with the pre-update version. However, you're missing security patches, which is a compliance and security risk. Fix the installation issue to apply updates—databases won't be affected by the repair process.

Q: After fixing 0x80070643, the same update fails again with a different error. What should I do?

A: This indicates you fixed the first problem but uncovered a second underlying issue. Download the standalone cumulative update from Microsoft Update Catalog and run it directly (bypassing Windows Update). Review the new SQL setup logs to identify the new error. Common secondary issues: prerequisite software missing (Visual C++ Redistributables), corrupted SQL Server services, or blocked network ports if SQL uses remote configurations.