UpTrajectory Review

Microsoft's September Patch Tuesday was a mess for a lot of businesses, and this piece catalogues the cleanup. The monthly update cycle fixed hundreds of security vulnerabilities, which is the part Microsoft wants you to focus on, but it also introduced a set of functional regressions that hit everyday workflows: Excel paste operations failing, Remote Desktop connections dropping or hanging at startup, Credential Guard-related identity problems in Active Directory, broken folder sharing for HCS-managed virtual machines including WSL, and USB Audio Class 1.0 devices going silent. Microsoft has now shipped a series of out-of-band updates to address several of these issues, which tells you the company knew it couldn't wait until October to fix them.

For a small business running Windows on a handful of machines, this is not an abstract IT story. If you applied the September updates and suddenly your bookkeeper can't paste into Excel, your remote workers can't connect to the office server, or your conference room audio is dead, that's lost time and real money. The Excel 2016 hotfix is only partial, which means some users will still need to use the 'Paste special' workaround. The Credential Guard issue is more concerning from a security standpoint: some devices lost recognition within Active Directory, and the interim fix involves temporarily disabling a security enforcement mechanism, which is the kind of trade-off no small operator wants to make without understanding the risk.

What is notable here is the pattern, not just the individual bugs. Patch Tuesday has always carried some regression risk, but the breadth of this month's problems — spanning productivity software, remote access, identity management, virtualization, and hardware audio — suggests a quality control problem that should worry anyone managing a mixed fleet of Windows machines. The out-of-band fixes are welcome, but they also create a new problem: IT teams that carefully stage updates now have to decide whether to rush these hotfixes into production or wait and leave users dealing with broken functionality. Neither option is great.

The Credential Guard issue deserves extra attention because the workaround involves weakening a security control, even temporarily. For businesses in regulated industries or those handling sensitive client data, that is not a casual decision. The fact that Microsoft has not yet shipped a permanent fix and is only promising one in a future update means this problem will linger. Meanwhile, the HCS/Plan9 issue affecting WSL and Claude Cowork users is a reminder that Microsoft's virtualization stack has become deeply intertwined with developer workflows, and a regression there ripples far beyond traditional IT departments.

If you manage Windows machines and applied the September updates, check whether any of these issues match what your users are reporting, and apply the relevant hotfixes from Microsoft's update catalog. If you have not yet applied the September patches, this is a good case for waiting a week or two after future Patch Tuesdays before rolling updates out broadly, or at minimum testing on a non-critical machine first. Microsoft will release its October updates soon; watch whether those introduce their own regressions before applying them across your fleet. The security fixes in these updates are real and necessary, but so is the disruption, and the trade-off is yours to manage.

“Microsoft fixed hundreds of security flaws in its September Patch Tuesday software updates — but it also introduced some annoying bugs.” — Computerworld

Takeaway: If September's Windows updates broke Excel, remote desktop, or audio on your machines, Microsoft has shipped hotfixes — but test before deploying and watch for lingering Credential Guard issues.