Microsoft confirms KB5002914 Excel update breaks copy and paste

Microsoft has confirmed that copy and paste may silently fail for some Excel users after installing the September 2026 KB5002914 security update.

This follows a wave of customer reports on Reddit and the Microsoft Q&A forums that the KB5002914 Office security update is breaking copy-and-paste, autofill, and formula dragging in Excel.

The company has confirmed these issues, saying they affect Microsoft Excel 2024, 2021, 2019, and 2016.

"Although users try to paste content, the source remains selected and the destination is unmodified," Microsoft said in an updated support document.

"When this issue occurs, users receive no indication of the failure, such as a beep or error message. Microsoft is researching the issue and will post more information in this article when the information becomes available."