Excel Security Patch Causes Copy-Paste and Autofill Failures for Some Users
Microsoft's September 2026 security update KB5002914 is reportedly breaking copy-and-paste operations and formula dragging in Excel for some users across multiple versions and installation methods. Affected users say that uninstalling the update or downgrading the Office build restores normal functionality. BleepingComputer could not reproduce the issue on a tested Excel 2019 build, and Microsoft has not yet acknowledged the problem.
The problematic patch, KB5002914, was issued as part of the September 2026 Patch Tuesday cycle. Complaints quickly surfaced on Reddit and Microsoft's official Q&A forums, with users reporting that core functions like formula dragging and keyboard shortcuts for copying had stopped working.
The defect appears to span various Office editions, including 2016, 2021, and 2024, and affects both MSI and Click-to-Run setups. While some users have successfully restored functionality by uninstalling the patch or rolling back the build, BleepingComputer's own testing on an Excel 2019 build did not replicate the failure. Microsoft has yet to issue an official statement.
This regression could significantly disrupt enterprise productivity, as copy-paste and autofill are fundamental to daily spreadsheet workflows. Organizations that automatically deploy security patches may find their teams temporarily blocked from critical data manipulation tasks. While the issue appears limited to specific configurations, the lack of an immediate vendor acknowledgment may force IT departments to choose between maintaining security compliance and restoring operational functionality. The broader impact hinges on how quickly Microsoft can isolate the root cause and provide a reliable fix.