Microsoft has fixed a known issue that causes copy-and-paste failures for Excel users after installing the September 2026 security updates.

The bug was confirmed following a wave of customer reports on Reddit and the Microsoft Q&A forums that this month’s updates (including the KB5002914 security update) break copy-and-paste, autofill, and formula dragging in Excel.

“In Microsoft Excel 2024, 2021, 2019, and 2016, as well as Excel Online in Office Online Server, the paste operation might fail silently,” Microsoft explains in a support document updated on Friday.