Microsoft has decided to remove a mandatory "registry key requirement" it introduced in the aftermath of the Meltdown and Spectre vulnerability disclosure.

Microsoft used this registry key to prevent Windows updates from being installed on computers running antivirus software incompatible with the Meltdown and Spectre patches.

Antivirus vendors were supposed to create this registry key on users' computers to signal that they've updated their product and will not interfere with Microsoft's patches. This was a big issue because incompatible antivirus products would crash and BSOD Windows systems.

Registry key requirement removed in Windows 10 last month

Microsoft said in January that Windows computers that use a custom antivirus product that does not add the registry key (hence is compatible with the Meltdown and Spectre patches) would not receive any Windows security updates.

But as antivirus vendors updated products and Microsoft's Meltdown and Spectre patches received more refinements, Microsoft decided to remove the mandatory registry key requirement.

The OS maker removed the registry key check for Windows 10 computers last month, in March, and has announced yesterday that the key is no longer necessary for the other Windows operating system versions —7, 8, 8.1, Server 2008, and Windows Server 2012.

Registry key removed in KB4093114 and KB4093118

"Windows Update and WSUS will offer this update to applicable Windows client and server operating systems regardless of the existence or value of the "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\QualityCompat\cadca5fe-87d3-4b96-b7fb-a231484277cc" registry setting. This change has been made to protect user data," said Microsoft in two updates —KB4093114 and KB4093118.

This new development means that users —mostly systems on large enterprise networks— that use custom antivirus products and who've stayed their hand in regards to the Meltdown and Spectre patches can now update without any fear of having their PCs enter a blue screen of death out of the blue.