[German]The Microsoft security updates released for Office applications on September 8, 2026, are causing serious collateral damage. In Excel, it is no longer possible to select and copy anything.
Note: Use the blog's build in translation feature to read the German blog posts linked below in English.
Office Updates from September 8, 2026
On September 8, 2026, Microsoft released a batch of security updates for the MSI versions of MS Office 2016, even though this version has long since reached end of support. In addition, the Click-2-Run versions of Microsoft Office 2016–2024 and the Microsoft 365 apps were updated. As for Office 2024, I'm currently unsure whether an update has been released. An overview of the updates can be found in the German blog post "Patchday: Microsoft Office Updates (8. September 2026)". It's primarily the numerous remote code execution (RCE) vulnerabilities that have been patched in the Office applications that have caught my attention.
Excel issues after September 2026 Updates installed
The security fixes in the September 2026 update seem to be causing serious problems. I've come across several reports about this.
Reader Comments within my German blog
German blog reader Michael posted this German comment around noon on September 9, 2026, reporting issues. The reader wrote (I've translated his comment):
In Office 2016, we can no longer copy a row and paste it into another row. Yesterday's Office updates have been installed.
I assume that "Office" here simply refers to Microsoft Excel 2016, where cells cannot be copied.
German blog reader Hackmanck confirms in this German comment that he is having problems copying cells in Excel. In addition, AutoFill no longer works. He is experiencing this issue with the MSI version of Microsoft Office 2016 (32-bit). In that version, updates can still be uninstalled; that is, uninstalling Update KB5002914 restores Microsoft Excel to full functionality. However, this is a security update for Excel 2016 that addresses various information disclosure and RCE vulnerabilities listed in the support article.
A Reader Report via Email
German blog reader Rainer F. contacted me via email on September 9, 2026, and confirmed serious Excel issues with the September 2026 updates for Microsoft Office.
I noticed that with yesterday's/today's update, both in Excel 2024 LTSC Pro and 2021 LTSC Pro, copy and paste within Excel isn't working; after a rollback, everything works again. Unfortunately, I haven't seen any further information yet.
I replied to Rainer that the problem had been confirmed by other readers on the blog.
Post on Microsoft Q&A
A blog reader referred to Microsoft Q&A in the comments on the forum post Excel 2016 Update Windows on 9 Sep 2026. The user reported that a problem with Excel 2016 occurred after the "Windows Update" on September 9, 2026. Copying and pasting no longer worked.
Another user stated that this behavior was caused by KB5002914. Other posters confirmed these issues with Office LTSC Standard 2021, noting that the affected user was unable to downgrade the Click-2-Run version.
Question on the patchmanagement.org mailing list
On the patchmanagement.org mailing list, in the thread titled "anyone seeing copy/paste issues in Excel Office 2019", Susan Bradley also asks whether anyone has noticed the limitations mentioned in the thread title following the September 2026 update. She is experiencing an issue where Excel lost its copy and paste functionality in Microsoft Office 2019 due to the update.
Notes on Rollback
To rollback Microsoft Office, you can use several ways. German blog reader Heiko describes within this German comment a GPO setting to pin the Office build to a specific version and, if necessary, force a rollback.
Sebastian has left this German comment mentions using an XML configuration file to perform a rollback by reinstalling. Microsoft has published this support article on rolling back to a previous version of Office.
Alternatively, it should be possible to perform a rollback via the command prompt after closing all Office applications.
"C:\Program Files\Common Files\Microsoft Shared\Microsoft\ClickToRun\OfficeC2RClient.exe" /update user updatetoversion=16.0.XXXXX.XXXXX
Specify the version with the desired string in the command.
Similar articles (German]:
Microsoft Security Update Summary (8. September 2026)
Patchday: Windows 10/11 Updates (8. September 2026)
Patchday: Windows Server-Updates (8. September 2026)
Patchday: Microsoft Office Updates (8. September 2026)
Exchange Server: Sicherheitsupdates (8. September 2026)
WSUS-Sync-Problem durch September 2026-Updates gefixt
September 2026-Updates fixen Mauszeiger- & Desktop-Wallpaper-Bugs und App-Crashes
