Broke 0.5 Vistas Fixed officially acknowledged Sep 8, 2026 their #44 worst broke on record

The September Office update quietly broke copy and paste in Excel

September 2026 Office update broke pasting in Excel with silent failures

↳ caused by September 2026 Office updates (KB5002914) ↗

The market's verdict: +1.1% on MSFT in the week after.

Status: Fixed. Working as intended, eventually.

What actually happened

The September 2026 Office security update broke pasting in Excel 2016, 2019, 2021, 2024 and Excel Online, with pastes failing silently, no error, no alert, no sound, just nothing happening, the most sinister possible failure mode for a spreadsheet. Microsoft's suggested workaround was to route the clipboard through Word or use Paste Special. Fixes landed September 21 to 23, with a note that users might have to manually trigger Office updates to get them. Excel users describe this entry to Access users for solidarity.

This one is officially acknowledged.

Were you affected? Unbreak it

Fixed in the September 21-23 Office updates ↗

Microsoft has acknowledged this issue; a fix ships in an out-of-band or next cumulative update. Check Windows Release Health before manual workarounds.

They did it more than once

Before that: Microsoft Access updates itself into refusing its own databases (Dec 2018)

An Office update breaking the most basic function available: 2018 Access, 2026 Excel.

Timeline

Sep 8, 2026 Confirmed First reports came in.
Sep 21, 2026 Fixed Fixed builds rolled out to all affected Office versions.