Microsoft's KB5002914 security update for Office, released as part of the September 2026 Patch Tuesday, has been reported to break copy-and-paste functionality and formula dragging in Excel. The issue affects various Office versions from 2016 to 2024 and different installation methods (MSI and Click-to-Run). Users have found that uninstalling the update or downgrading Office builds restores functionality. Some users have attempted replacing the updated excel.exe with an older version, but this is not recommended due to potential stability and security risks. Microsoft has been contacted for comment but has not yet provided an official response or workaround.

The update disrupts core Excel functionalities such as copy-and-paste and formula dragging, which can significantly hinder productivity for affected users. The issue blocks normal workflow in Excel but does not represent a security vulnerability or exploit. There is no evidence of exploitation or security compromise related to this update.

Affected users can uninstall or roll back the KB5002914 update to restore Excel functionality. For MSI-based Office installations, uninstalling the update via provided PowerShell commands has been effective. For Click-to-Run installations, downgrading the Office build using XML or Group Policy is a workaround. Replacing the excel.exe executable with an older version is not recommended due to potential stability and security risks. Monitor official Microsoft channels for updates or patches addressing this issue.