Some devices might freeze at boot due to this bug

Apr 12, 2019 08:23 GMT  ·  By

A bug introduced by the latest Windows 7 and 8.1 monthly rollups causes devices running these two Windows versions to freeze at boot.

However, it looks like the problem is only encountered on computers running certain antivirus software, including security products developed by Sophos.

Microsoft acknowledged the issue, but said it’s only experienced with Sophos software. The company blocked the updates from being offered to devices running Sophos antivirus.

“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,” the company says.

Nevertheless, similar issues are experienced on devices where other antivirus products are installed, and Avast has recently confirmed that its customers are impacted too.

“Avast has received reports of an issue affecting our customers running Avast for Business and Avast CloudCare on Windows machines, particularly those with Windows 7 operating systems. While this problem is currently being researched, we have discovered some temporary solutions to restore functionality to our users,” the security vendor explains.

Office patches could cause issues too

However, the bug freezing devices isn’t only caused by Windows monthly rollups, but also by a series of other updates, including Office patches. Avast says the following updates could make the system hang on boot: KB4462223, KB4493472, KB4493448, KB4464520, KB4462230 and KB4493435.

While a full fix is currently being developed, Avast recommends its customers to completely uninstall the updates. You can also reach out to customer support if you can’t apply this fix.

Microsoft hasn’t provided any ETA as to when a solution to these bugs would be released, but for now, the update block could be expanded to cover more devices running security products from other vendors too.

If you haven’t installed this month’s monthly rollups, you should avoid doing it until patch reliability becomes clear.