Microsoft's September patches break Remote Desktop, USB audio and Excel paste

Microsoft has confirmed that its latest security updates shipped with three separate known issues: Remote Desktop Services that stop working across several Windows versions, USB audio devices that lose sound, and an Excel patch that breaks pasting without any error message. According to The Register, the batch of flaws sits awkwardly with the company's repeated insistence that it is getting update quality under control.

Remote Desktop connections fail and management tools hang

Problems with Remote Desktop Services (RDS) began circulating on social media shortly after the update landed, and Microsoft has now acknowledged that the service is genuinely broken for some users. Affected releases include Windows 11 26H1 and Windows Server 2012 — the latter is due to leave the Extended Security Updates program on 13 October 2026, which The Register wryly suggests administrators may regard as a farewell gift from Redmond.

The symptoms go well beyond dropped sessions. Microsoft says connections may fail after a few minutes, and servers may hang at the "Please wait for the Remote Desktop Configuration" screen. The Microsoft Management Console, the RDS Licensing Diagnoser and File Explorer can also become unresponsive, and the Windows Update page may sit on a loading indicator indefinitely. Where a virtual machine becomes unreachable over RDP, deallocating and restarting it can temporarily restore connectivity. A fix is in progress.

USB audio devices go silent on Windows 11

Microsoft also confirmed issues affecting some USB Audio Class 1.0 devices on Windows 11 24H2, 25H2 and 26H1. Although the specification originated in the last century, affected users can end up with no audio at all, broken sound settings and volume controls, or problems with multichannel playback. Some customers have recovered sound by switching their device into two-channel mode, Microsoft says. The company is working on a fix but has not offered a timeline.

Excel paste fails without warning

The productivity side did not escape either. A patch intended to address remote code execution and information disclosure vulnerabilities in Excel has instead broken a basic spreadsheet function. According to Microsoft, the paste operation "might fail silently" in Excel 2016, 2019, 2021 and 2024: the source remains selected, the destination is left unmodified, and users receive no beep or error message indicating that anything went wrong.

Because the update may already have been downloaded and installed automatically, users could be affected without realising it. Microsoft has not published a workaround. The Register reports that one forum user resolved the problem by uninstalling and reinstalling Office, while others succeeded by removing the security update with commands — an approach that also strips out the security protections the update provided.

Why it matters

Individually, each issue is an inconvenience; together, they illustrate why patching Windows and Office has become an exercise in risk management. An RDS failure can lock administrators out of their servers, and the only documented workaround — deallocating and restarting a VM — does not help with physical machines. The silent Excel paste failure is arguably the most dangerous of the three: a spreadsheet can look perfectly fine while simply missing the pasted data, with nothing to alert the user. And the remedy of last resort, removing the patch, means giving up fixes for remote code execution flaws. As The Register notes, a known-issues list this long so soon after release suggests Microsoft's quality drive still has a long way to go.