Windows 7 problems: Microsoft blocks April updates to systems at risk of freezing

Microsoft halts Windows 7 patches for Sophos users after updates trigger boot failures, which also affect Avast users.

Microsoft has blocked this week’s monthly and security-only Windows 7 and Windows 8.1 updates for Sophos antivirus users after widespread reports that computers failed to boot after installing them.

The updates caused dire problems for Windows 7 and Windows 8.1 systems running Sophos Endpoint Security and Control and Sophos Central Endpoint Standard/Advanced. The same issues affect their corresponding Server versions, Windows Server 2008 R2 and Windows Server 2012.   

The problems are caused by Microsoft’s Tuesday Windows 7 and Windows 8.1 monthly rollup and security-only updates KB4493467, KB4493446, KB4493448, KB4493472, KB4493450 and KB4493451.

“Microsoft and Sophos have identified an issue on devices with Sophos Endpoint Protection installed and managed by either Sophos Central or Sophos Enterprise Console (SEC) that may cause the system to freeze or hang upon restart after installing this update,” Microsoft said in an update on Thursday morning, European time.

Sophos has warned customers against installing these updates if they have not done so already. Customers this week report that computers have been failing to boot after installing them.

Sophos is telling users who have installed the update to boot into safe mode, disable Sophos antivirus, then boot into normal mode and uninstall the problematic Windows update. After that, users should re-enable Sophos antivirus.

As reported by Ask Woody, the Windows 7 updates also appear to be causing issues with systems running Avast antivirus.   

Avast says Windows 7 machines in particular “are becoming locked or frozen on startup after Microsoft updates KB4493472, KB4493448, and KB4493435”.


Microsoft hasn’t listed a block on the updates for Avast users.

Avast customers with Avast for Business and Avast Cloud Care, primarily on Windows 7, have reported machines becoming “stuck or frozen on the login/Welcome screen”. Some users cannot log in at all, while other users can log in after a “very extended period of time”.

Avast says some customers have been able to log in after booting the machine into Safe Mode and also recommends rolling back the Windows updates.

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