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Microsoft confirms it accidentally broke copy and paste in Excel with a major security update you shouldn’t remove
Microsoft released KB5002914, a security update for Excel, on September 8 that inadvertently disabled copy‑and‑paste across all supported versions, including 2016, 2019, 2021, and 2024. The bug causes silent paste failures, leaving source cells selected while destinations remain unchanged, and has been reported by users on Windows 10 and Windows 11. Microsoft acknowledged the issue, confirmed it is investigating, and advised against uninstalling the update due to critical security patches. No workaround is currently available.