How to Fix Fix Error 0x80070661 — Installation Package Architecture Mismatch on Windows
Getting error 0x80070661 during software installation? "This installation package is not supported by this processor type"? 32-bit vs 64-bit mismatch? Fix this architecture compatibility error.
Symptoms
You might be experiencing this problem if you notice:
- •Software installation fails with error 0x80070661
- •MSI package won't install claiming wrong processor type
- •Windows Update fails for specific architecture-dependent updates
- •Driver installation fails with processor mismatch error
- •Office or application update fails with this code
- •Sideloaded app won't install on this system
Common Causes
- ⚠Trying to install 32-bit package on 64-bit system (or vice versa)
- ⚠Downloaded wrong architecture version of software
- ⚠Windows Update delivered wrong architecture patch
- ⚠MSI package built for ARM but running on x86/x64
- ⚠Corrupted Windows Installer registration showing wrong platform
- ⚠Group Policy deploying wrong architecture MSI
Solutions
Solution 1: Install Correct Architecture Version
- 1First check your system architecture:
- 2Settings → System → About → System type
- 3Shows "64-bit operating system, x64-based processor" or similar
- 4Download the matching version of the software:
- 5For 64-bit Windows: download the x64 or AMD64 version
- 6For ARM Windows: download the ARM64 version
- 7For 32-bit Windows: download the x86 or 32-bit version
- 8Most modern software offers separate downloads per architecture
- 9If only 32-bit available: it should work on 64-bit via WoW64
Solution 2: Fix Windows Installer Registration
- 1If correct architecture and still failing:
- 2CMD as Admin:
- 3msiexec /unregister
- 4msiexec /regserver
- 5Re-register 32-bit MSI engine on 64-bit systems:
- 6C:\Windows\SysWOW64\msiexec.exe /regserver
- 7Repair .NET Framework (common dependency):
- 8Download .NET Framework Repair Tool from Microsoft
- 9Run it → it fixes common .NET registration issues
- 10Restart PC → retry installation
Solution 3: Fix Windows Update Architecture Issues
- 1If Windows Update is delivering wrong architecture:
- 2This is rare but can happen with driver updates:
- 3Settings → Windows Update → Update history
- 4Find the failing update → note KB number
- 5Go to Microsoft Update Catalog (catalog.update.microsoft.com)
- 6Search the KB number → download correct architecture version
- 7Install manually by double-clicking the .msu file
- 8If a driver: Device Manager → right-click device → Update driver
- 9Browse my computer → pick the correct driver manually
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