Microsoft has advised organisations affected by the Windows 7 activation bug introduced last week to uninstall an old update that, it claims, is responsible for it.
The bug affected enterprise installations of Windows 7 that had an old patch installed, KB971033, which had contained anti-piracy features intended for retail activation, rather than enterprises. This patch should not have been installed on enterprise versions of Windows 7 where the organisation runs Key Management Service (KMS) or Multiple Activation Key (MAK) to perform volume activation, according to Microsoft.
The bug was inadvertently introduced by its own engineers during maintenance to the company's activation server. It coincided with last week's Patch Tuesday, leading to speculation that one of the patches that had been rolled-out was responsible. The company subsequently revealed that the bug had not been caused by Patch Tuesday, but by a server-side code change by Microsoft.
In a support article published on Thursday, the company admitted the problem: “A recent update to the Microsoft Activation and Validation unintentionally caused a “not genuine” error on volume-licensed Windows 7 clients that had KB 971033 installed. The change was introduced at 10:00:00 UTC on January 8, 2019, and was reverted at 4:30:00 UTC on January 9, 2019.”
The clash between KB971033 and Microsoft's own Key Management Service (KMS) affects the following versions of Windows 7:
- Windows 7 Professional;
- Windows 7 Professional N;
- Windows 7 Professional E;
- Windows 7 Enterprise;
- Windows 7 Enterprise N;
- Windows 7 Enterprise E.
In addition to the activation issues, the bug also prevented systems administrators from remotely accessing network shares. An update to Windows 7 SP1 and Windows Server 2008 has been released to fix this problem.