How to Fix Fix Error 0x80070645 — Windows Installer Service Failed on Windows
Getting error 0x80070645 during Windows Update or software installation? Installer service returned an error? MSI package failed? Fix this Windows Installer error.
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Main Troubleshooting Guide
How to Fix Windows Update Errors →Complete symptoms, causes, and step-by-step solutions
Symptoms
You might be experiencing this problem if you notice:
- •Windows Update fails with error 0x80070645
- •Software installation aborts with this error code
- •.NET Framework updates fail with 0x80070645
- •MSI packages fail to install or uninstall
- •Feature updates stuck referencing installer service
- •Security updates repeatedly fail with this error
Common Causes
- ⚠Windows Installer service corrupted or stopped
- ⚠.NET Framework installation damaged
- ⚠Previous installation left partial state
- ⚠Windows Installer registration corrupted in registry
- ⚠Conflicting software blocking installer operations
- ⚠Insufficient permissions for installer service
Solutions
Solution 1: Repair Windows Installer Service
- 1CMD as Admin:
- 2net stop msiserver
- 3net start msiserver
- 4If service won't start: re-register it:
- 5msiexec /unregister
- 6msiexec /regserver
- 7Restart PC
- 8Retry the failed update or installation
Solution 2: Repair .NET Framework
- 1Download Microsoft .NET Framework Repair Tool:
- 2Search: "Microsoft .NET Framework Repair Tool" on microsoft.com
- 3Run the tool — it fixes common .NET issues automatically
- 4If specific .NET version is failing:
- 5Settings → Apps → Optional features
- 6Find .NET Framework versions → remove and re-add
- 7Or: DISM /Online /Enable-Feature /FeatureName:NetFx3 /All
- 8Restart PC → retry update
Solution 3: Reset Windows Update Components
- 1CMD as Admin:
- 2net stop wuauserv
- 3net stop cryptSvc
- 4net stop bits
- 5net stop msiserver
- 6ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
- 7ren C:\Windows\System32\catroot2 catroot2.old
- 8net start wuauserv
- 9net start cryptSvc
- 10net start bits
- 11net start msiserver
- 12Run: sfc /scannow && DISM /Online /Cleanup-Image /RestoreHealth
- 13Retry Windows Update
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