How to Fix Fix Error 0x8007066D — Windows Installer Transaction Rollback Required on Windows
Getting Windows error 0x8007066D? Installer transaction rollback required? Software installation rolled back? MSI transaction failed and reverted? Installation changes undone? Fix error code 0x8007066D.
📖
Main Troubleshooting Guide
How to Fix Microsoft Store Not Working →Complete symptoms, causes, and step-by-step solutions
Symptoms
You might be experiencing this problem if you notice:
- •Software installation fails and rolls back with error 0x8007066D
- •MSI installer starts then reverts all changes
- •Windows component installation triggers rollback
- •Feature update fails during transaction commit phase
- •Multiple retries always end in rollback at same point
- •Event log shows installer transaction failure
Common Causes
- ⚠Insufficient disk space for transaction journaling
- ⚠Windows Installer transaction log corrupted
- ⚠File in use by another process preventing replacement
- ⚠Antivirus blocking file modifications during install
- ⚠Previous incomplete installation left orphaned transactions
- ⚠System policy restricting installer modifications
Solutions
Solution 1: Free Disk Space and Clean Temp Files
- 1Check available disk space:
- 2File Explorer → This PC → check C: drive free space
- 3Need at least 10 GB for transaction journaling
- 4Clean temporary files:
- 5Settings → System → Storage → Temporary files
- 6Check all categories and click Remove files
- 7Also clean installer cache:
- 8CMD as Admin:
- 9DISM /Online /Cleanup-Image /StartComponentCleanup
- 10This removes superseded component versions
- 11Retry installation
Solution 2: Close Conflicting Processes
- 1Close all running applications before installing
- 2Disable antivirus real-time protection temporarily
- 3Check for locked files:
- 4If error mentions a specific file:
- 5Open Task Manager → Details tab
- 6Look for processes using that file
- 7End those processes
- 8Run installer in Safe Mode:
- 9Boot into Safe Mode with Networking
- 10Run the installer from Safe Mode
- 11This prevents most conflicts
Solution 3: Reset Windows Installer Service
- 1Re-register Windows Installer:
- 2CMD as Admin:
- 3msiexec /unregister
- 4msiexec /regserver
- 5Clear transaction logs:
- 6Delete files in C:\Windows\Installer\$PatchCache$ (if very large)
- 7Do NOT delete the Installer folder itself
- 8Repair system files:
- 9sfc /scannow
- 10DISM /Online /Cleanup-Image /RestoreHealth
- 11Restart PC and retry installation
FIXES THIS IN 5 MINUTES
Fix Fix Error 0x8007066D — Windows Installer Transaction Rollback Required Automatically
RescuePC Toolkit includes 109+ automated repairs that fix this problem with one click. No command line knowledge required.
Download Now - Free TrialNo credit card required • Works on Windows 10 & 11