Security1 publisher2 min readPublished
Microsoft ships four manual patches for the Excel paste failure September's updates caused
Paste, autofill and formula dragging stop working in Excel 2016 through Office LTSC 2024 after September's security updates, with nothing on screen to flag the failure. The repair is four version-specific packages installed by hand.
The Watch · Security desk
What happened
- Microsoft confirmed that its September 2026 Office security updates, including KB5002914, break copy-and-paste, autofill and formula dragging in Excel, after reports on Reddit and the Microsoft Q&A forums.
- The support document says the paste operation can fail silently in Excel 2024, 2021, 2019 and 2016 and in Excel Online in Office Online Server, leaving the source selected and the destination unmodified.
- Microsoft says paste can still fail where a workbook contains conditional formatting, and offers Paste Special as a temporary workaround until a permanent solution for that case exists.
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Why it matters
- cost Every environment that deployed September's Office baseline now owes a second rollout, and the four packages have to be matched to the Office version installed on each machine.
- exposure Because nothing on screen flags the failure, unchanged cells travel into reports and downstream workbooks while the user believes the paste landed.
- precedent A fourth Office functional break fixed in 2026 strengthens the internal case for holding Office security updates back a month for testing.
Excel does not report the failure. "Although users try to paste content, the source remains selected and the destination is unmodified. When this issue occurs, users receive no indication of the failure, such as an error message or alert with sound," Microsoft wrote in a support document that BleepingComputer says was updated on Friday [4]. A user copies a range, clicks the destination, presses Ctrl+V and moves on. The cells are unchanged.
The remediation is four packages keyed to version: KB5002665 for Excel 2016, build 10417.20208 for Office LTSC 2019, build 14334.20918 for Office LTSC 2021, and build 17932.21000 for Office LTSC 2024 [5][11]. Affected users have to download and install them themselves [5]. An estate running more than one Office version matches each machine to the right build and pushes all four, weeks after the security baseline went out [2].
The patch leaves one case open. Microsoft warns that paste can still fail where a workbook contains conditional formatting, and points users to Paste Special until a permanent fix for that case is available [6][7]. Paste Special sits in the Paste drop-down on the Home tab, or on Ctrl+Alt+V, with a choice of Formula, Formula and number formats, Values, Values and number formats, or Paste Link [8].
The versions Microsoft named are Excel 2024, 2021, 2019 and 2016, plus Excel Online in Office Online Server [3]. All four remediation builds are Excel 2016 or Office LTSC releases [5].
Microsoft describes a functional break [3]. What it costs security teams is the credibility of the monthly baseline. By BleepingComputer's account this is the fourth Office functional regression Microsoft has fixed in 2026: two in June, one blocking Windows 365 users from downloading the Office suite and one blocking Office for the web users from opening Excel and PowerPoint documents; one in July, which stopped third-party apps launching Word, Excel, PowerPoint and Access; and this one [9][10][12]. KB5002914 shipped as a security update [2].
What to watch
- Whether Microsoft ships the permanent fix for conditional-formatting workbooks, and whether it arrives through normal update channels instead of a manual download.
- Whether Microsoft 365 Apps builds are added to the affected-version list in the support document.
- Whether the four LTSC and Excel 2016 fix builds are later offered automatically.