KB5132061 failed to install 10 times with error code 0x80070306

You have conflicting evidence: repeated 0x80070306 failures, a success event and files present in WinSxS. A component folder alone does not establish that the cumulative update completed. First record winver: Microsoft lists KB5132061 as builds 26300.9974, 26200.9974 or 26100.9974, depending on Windows version. In elevated PowerShell, run Get-WindowsPackage -Online and inspect the relevant servicing package’s state; distinguish Installed from Staged or InstallPending. An empty update history after cache cleanup is not a substitute for checking the installed build and package state. Before deleting more folders, preserve CBS and Windows Update logs and correlate the latest failure timestamp with the exact package being processed. Also check the release note’s prerequisites for your Windows version before another manual installation. I cannot identify the cause from 0x80070306 alone. Please add your Windows version, current build and package-state result to your existing Feedback Hub report, with sensitive log information removed.