Microsoft fixes Excel copy-and-paste failures after September updates

Microsoft has fixed a known issue that caused copy-and-paste failures in Excel after users installed the September 2026 security updates, according to BleepingComputer. Customer reports on Reddit and the Microsoft Q&A forums linked the problem to the KB5002914 security update.

Microsoft said in a support document that, in Excel 2024, Excel 2021, Excel 2019, and Excel 2016, as well as Excel Online in Office Online Server, paste operations could fail silently. The source would remain selected while the destination stayed unchanged, without an error message or sound alert.

Affected users must manually install updates for Excel 2016 (KB5002665), Office LTSC 2019 (Build 10417.20208), Office LTSC 2021 (Build 14334.20918), and Office LTSC 2024 (Build 17932.21000). Microsoft warned that pasting might still fail when a workbook contains conditional formatting. Until a permanent fix is available for that case, it recommends using Paste Special from the Paste menu under the Home tab, or opening it with Ctrl+Alt+V and selecting the required paste option.