Microsoft confirms September 2026 Excel update breaks copy‑paste function

Microsoft officially acknowledges that the copy‑and‑paste operation can fail for certain Excel users who apply the September 2026 security update known as KB5002914.

The issue was first brought to light by a report on the security‑oriented site bleepingcomputer, which detailed users encountering silent failures—data seems to be copied to the clipboard yet nothing is pasted inside Excel.

Microsoft, in a short statement, admitted the flaw and indicated it seems confined to a narrow range of system configurations. The firm is working on a corrective patch and recommends that affected users remove the KB5002914 update or revert to the prior version until a solution is available.

Copy‑and‑paste underpins virtually every Excel task, from basic data entry to sophisticated analysis and reporting. When it stops working, everyday workflows can be disrupted, project schedules delayed, and users forced to resort to manual re‑typing or other transfer techniques.

The episode highlights how challenging it can be to push cumulative monthly updates to a worldwide, varied user base. Microsoft generally releases security patches on the second Tuesday of every month, and when regressions appear, it strives to deliver corrective updates within a few weeks. IT administrators should monitor Microsoft’s release notes and trial upcoming updates in controlled settings before widespread rollout.