Microsoft confirms security update broke Excel copy and paste

Microsoft ↗ 1.97% has confirmed that its September 2026 Patch Tuesday security update, KB5002914, silently breaks copy-and-paste functionality across multiple versions of Excel, leaving users unable to perform one of the application's most fundamental operations.

The company acknowledged the bug in an updated support document after a wave of user complaints surfaced on Reddit and Microsoft's Q&A forums following the update's release last week. The issue affects Excel 2016, 2019, 2021, and 2024, and also disrupts autofill and formula dragging.bleepingcomputer

A Silent Failure

What makes the bug particularly frustrating is that it provides no feedback when it occurs. "Although users try to paste content, the source remains selected and the destination is unmodified," Microsoft said in its support document. "When this issue occurs, users receive no indication of the failure, such as a beep or error message."itpro+2

Microsoft said it is still researching the problem and has not yet issued a fix. The bug is the only known Excel issue introduced by KB5002914.neowin+2

A Workaround Exists — With Trade-offs

While Microsoft has yet to deliver an official patch, affected users have found that uninstalling KB5002914 restores normal copy-and-paste behavior. BleepingComputer published command-line instructions for rolling back the update across different Office versions, though doing so would also remove the security fixes the update was designed to deliver.bleepingcomputer

KB5002914 was released as part of Microsoft's September 2026 Patch Tuesday to address a list of remote code execution and information disclosure vulnerabilities. Users who uninstall the update to restore Excel functionality would therefore be reverting those security patches as well.bleepingcomputer

A Familiar Pattern

The Excel bug is the latest in a string of issues tied to Microsoft's monthly update cycle. In May, a Patch Tuesday update caused images not to display in mail, and in June, another update hid the main body of email messages. Microsoft also released emergency out-of-band updates on Monday to resolve Remote Desktop Services failures caused by the same September 2026 security updates, along with Hyper-V and USB audio problems on some Windows versions.itpro+2

For now, Excel users face an uncomfortable choice: keep the security update and lose copy-paste, or roll it back and lose the protections it was meant to provide.