Patch Regression: KB5002934 (October 2026) breaks copy/paste fix originally provided by KB5002665 in Excel 2016 MSI

Narciso Gonzalez 0 Reputation points
2026-10-14T16:11:30.66+00:00

Issue Description: The silent copy/paste failure in Excel 2016 (MSI) has returned immediately after installing the cumulative update KB5002934 (released October 13, 2026).

Technical Analysis:

  • Environment: Excel 2016 MSI (Traditional Volume License installer).
  • Build Version: EXCEL.EXE build 16.0.5574.1004.
  • Root Cause: The new cumulative patch KB5002934 replaces/supersedes the September hotfix KB5002665 but fails to include the clipboard regression fix. As a result, the "silent copy-paste bug" with conditional formatting has been re-introduced into the production line.
  • Temporary Workaround verified: Uninstalling KB5002934 and blocking it from Windows Update restores normal clipboard functionality.

Please escalate this to the Excel product development team for a hotfix re-pack.

Microsoft 365 and Office | Excel | For business | Windows

1 answer

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  1. Hendrix 2,075 Reputation points Independent Advisor
    2026-10-14T16:54:50.9066667+00:00

    Hi Narciso,

    Greatly appreciate your information. The silent paste issue was previously documented for Excel 2016 MSI after KB5002914, and Microsoft released KB5002665 on September 16 to address that issue.

    KB5002934 is the October 13, 2026 security update for Excel 2016 MSI, and Microsoft documents it as replacing KB5002914. However, the currently published documentation, Description of the security update for Excel 2016: October 13, 2026 (KB5002934) | Microsoft Support, does not confirm that KB5002934 reintroduced the paste issue or that it omitted the fix from KB5002665. Since the issue began immediately after installing KB5002934 and normal functionality returned after removing it, the results provide strong evidence of a possible regression.

    Therefore, I highly recommend reporting this issue to Microsoft as a suspected regression associated with KB5002934 through Excel > Help > Feedback > Report a problem. If you're using a work/school account, please ask your IT administrator to use the Report an issue option in the Microsoft 365 Admin Center > Health > Service Health to help raise visibility and provide additional diagnostic information to Microsoft. This allows them to review and acknowledge the issue, which can help prioritize a fix as soon as possible.

    I will also continue to monitor the situation and keep you informed of any new information as it becomes available.

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