Windows Update problems: What went wrong? Watch Now

Microsoft's April 2019 security updates and monthly rollups are turning into a bigger problem than originally known.

Last week Windows 7 users with Sophos and Avast antivirus began reporting problems after installing Microsoft's April 9 updates.

As ZDNet reported, users suggested that Windows 7, Windows 8.1, Windows Server 2008 R2, and Windows Server 2012 were failing to boot after installing the security-only and monthly rollup updates.

Despite user reports of boot problems affecting Avast users, Microsoft at the time only confirmed problems affecting Sophos users.

SEE: 20 pro tips to make Windows 10 work the way you want (free PDF)

And while there were some reports of similar issues and slowdowns affecting Windows 10 after installing the April 2019 updates, they were not widespread and not necessarily caused by Microsoft's April software updates.

Microsoft has now confirmed that there is an antivirus clash that affects Windows 10 version 1809 but only in relation to ArcaBit, a little-known Polish antivirus vendor.

"Microsoft and ArcaBit have identified an issue on devices with ArcaBit antivirus software installed that may cause the system to become unresponsive upon restart after installing this update," Microsoft said in update on Saturday to known issues affecting Windows 10 1809.

Microsoft has also identified a problem affecting the rename operation in Cluster Shared Volume (CSV) folders. It will fix that issue in a future update. This issue affects Windows 10 and Windows 8.1 and Windows Server 2012 but not Windows 7.

"Certain operations, such as rename, that you perform on files or folders that are on a Cluster Shared Volume (CSV) may fail with the error, 'STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)'. This occurs when you perform the operation on a CSV owner node from a process that doesn't have administrator privilege."

The Windows maker has now implemented a block on the April updates for Avira users on Windows 7, Windows 8.1 and their corresponding Windows Server versions.

"Microsoft has temporarily blocked devices from receiving this update if Avira antivirus software is installed. We are presently investigating this issue with Avira and will provide an update when available," Microsoft notes.

The company also confirmed boot problems affecting Avast for Business, Avast CloudCare, and AVG Business Edition on Windows 7. Avast has released 'emergency updates' to fix this problem for customers and details the procedures to resolve problems in a support note.

"Microsoft and Avast have identified an issue on devices running Avast for Business, Avast CloudCare, and AVG Business Edition antivirus software after you install this update and restart. Devices may become unresponsive at the login or Welcome screen. Additionally, you may be unable to log in or log in after an extended period of time," Microsoft explains.

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