A Critical Issue Fixed: Microsoft Resolves Broken Copy-Paste Functionality in Excel
Microsoft has addressed a significant problem affecting Excel users after installing its September 2026 security updates. The issue, which was confirmed by customer reports on Reddit and the company’s Q&A forums, causes copy-and-paste operations to fail silently without providing any error messages or alerts.
The affected software includes Microsoft Excel 2024, 2021, 2019, and 2016, as well as Excel Online in Office Online Server. When attempting to paste content, users may notice that the source remains selected, while the destination remains unmodified. This issue is particularly frustrating because it occurs without warning or notification.
To resolve this problem, affected users must manually download and install updates for specific Excel versions: KB5002665 for Excel 2016, Build 10417.20208 for Office LTSC 2019, Build 14334.20918 for Office LTSC 2021, and Build 17932.21000 for Office LTSC 2024.
A temporary workaround is available for users whose paste operations continue to fail due to conditional formatting in their workbooks. Microsoft recommends trying the “Paste Special” option as a quick fix until a permanent solution for this specific scenario is released. To do so, users should click on “Paste Special” within the “Home” tab and use the Ctrl+Alt+V keyboard shortcut to select the desired paste options.
This issue highlights the importance of staying up-to-date with software updates and patches. Microsoft has previously addressed similar problems in recent months, including an issue that blocked Windows 365 users from downloading Office, another that prevented Office for web users from opening Excel documents, and a problem that stopped third-party apps from launching Microsoft Office applications.
As AI-powered attacks become increasingly prevalent, it’s essential to maintain robust cybersecurity measures. This includes keeping software and applications updated with the latest security patches, being aware of potential issues like the one described here, and using temporary workarounds until permanent solutions are available.
To minimize the risk of encountering similar problems in the future, users should prioritize updating their software regularly and be vigilant about potential issues that may arise. By doing so, they can ensure uninterrupted productivity and maintain a secure digital environment.
Source: Bleeping Computer — 2026-09-21