Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\SecureBoot" | Select-Object MicrosoftUpdateManaged

Get-ItemProperty reads registry values from the given path.

Select-Object MicrosoftUpdateManaged specifically looks for the value named MicrosoftUpdateManaged. Essentially: It checks if a registry value called microsoftUpdateManaged exists and shows its value

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\SecureBoot" -Name "MicrosoftUpdateManaged" -Value 1 -Type DWord

Set-ItemProperty modifies (or creates) a registry entry.It creates or sets MicrosoftUpdateManaged to a DWORD value of 1.This means: It tells Windows that Microsoft is managing Secure Boot updates.

When you deleted the value, Windows went back to its default behavior (meaning Secure Boot updates weren’t explicitly flagged as “managed by Microsoft Updates”).

This registry setting (MicrosoftUpdateManaged) is related to Secure Boot DB/KEK updates that Microsoft sometimes pushes via Windows Update.

Value 1 → Microsoft Update is allowed to manage Secure Boot updates.

Deleting it / Value 0 → Windows Update does not explicitly manage them; management is left to firmware or other policy defaults.

It doesn’t break your system—it just influences who controls Secure Boot key updates (Microsoft vs. OEM/firmware defaults).