KB5068221 Targets App-V Virtualization Issues
Microsoft has unveiled an unscheduled out-of-band Windows 11 update, KB5068221, specifically designed to address persistent issues affecting Microsoft Office applications within virtualized Application Virtualization (App-V) environments. At the heart of the matter lay a double handle closure bug within the AppVEntSubsystems32 or AppVEntSubsystems64 component, which was successfully rectified by this latest update.
The cobbling together of fixes within KB5068221 not only touches on this pressing virtualization problem but also incorporates a raft of security patches and other improvements introduced in the prior update, KB5065426. Microsoft describes this release as bringing “quality improvements,” underscoring its commitment to refining user experiences.
Addressing SMBv1 Connectivity Concerns
While KB5068221 alleviates specific Office application glitches in App-V settings, it falls short of resolving another concern that has emerged recently following Microsoft's September updates: connectivity hitches with the Server Message Block (SMB) v1 protocol over NetBIOS over TCP/IP. Systems that adopted updates post-September 9, 2025, face hurdles in accessing shared files over SMBv1 if either server or client applied the September security patches. Notably, newer versions of SMB remain unaffected as SMBv1 and NetBIOS are marked deprecated.
For users grappling with this issue, Microsoft suggests allowing network traffic on TCP port 445. This strategy fosters automatic switching of SMB connections from NetBT to TCP, reestablishing reliable connectivity. Meanwhile, Microsoft is diligently working on a permanent fix to be included in a prospective Windows update.
Installation Guidelines for KB5068221
Users can procure KB5068221 directly from the Microsoft Update Catalog. The update contains one or more MSU files that necessitate installation in a defined order. The process offers two methods: either place all MSU files in the same directory and install using DISM (example command:
As a final step, users adding this update to images should ensure compatibility by either aligning with matching Dynamic Update package versions or opting for the most current versions available.
