Starting with Windows 10, version 1803, the "RegBack" copy functionality is not "broken" but was intentionally disabled by Microsoft to reduce the operating system's overall disk footprint. When you check the \Windows\System32\config\RegBack folder, you will often find registry hive files that are 0 KB in size, meaning no actual backup exists. Why the Feature was Removed
Step 5: Double-click it and set the Value data to 1. regback copy not working
Restart and Run Task: Restart your computer. To trigger the backup immediately, open Task Scheduler and run the RegIdleBackup task found under Microsoft\Windows\Registry. Alternative: Manual Backups Starting with Windows 10, version 1803, the "RegBack"
To confirm the issue is related to the OS version change rather than file corruption or permissions: Starting with Windows 10