# Microsoft Resolves Recurring Excel 2016 Copy-Paste Bug A persistent software glitch in Excel 2016 has been patched for the second time. - **Source:** [www.theregister.com - Articles](https://www.theregister.com) - **Published:** 2026-11-05 - **Topic:** [technology](https://brifing.si/c/technology) - **Original article:** - **On Brifing:** https://brifing.si/s/81dff9a1-b6e4-44d7-b048-c9a29ac4445b ## Persistent Paste Failure Microsoft has released a new build for Excel 2016, numbered 16.0.5574.1006, to address a recurring copy-paste bug. The issue caused silent failures where content would not paste into destination cells despite user input. This malfunction first appeared in September, was initially resolved, but surfaced again following the October security update cycle. ## Conditional Formatting Conflict The technical root of the failure involves workbooks containing conditional formatting rules. When these specific formatting elements are present, the paste operation fails to execute correctly. Microsoft confirmed this specific interaction in their release notes, noting that the bug was inadvertently reintroduced in the previous build, 16.0.5574.1005, during the October patch deployment. ## Update Cycle Complications The bug was linked to the KB5002934 security update, which was designed to patch remote code execution and information disclosure vulnerabilities. Users discovered that rolling back this specific update temporarily restored copy-paste functionality. However, Windows Update automatically re-applied the patch, causing the frustrating cycle of recurring failures for many enterprise workstations. ## Enterprise Impact Reported Reports from Microsoft Excel forums indicate that the issue affected entire organizations rather than isolated individual users. IT administrators faced significant workflow disruptions as the bug reappeared shortly after the initial fix. The recurrence caused frustration among professional users who rely on consistent spreadsheet functionality for their daily data management and reporting tasks. ## Scope of the Issue The problem is strictly confined to the Excel 2016 version and is not a result of broader Windows operating system security updates. While the bug is specific to this software iteration, its reappearance highlights challenges in regression testing. Microsoft has not provided a detailed explanation regarding how the bug slipped back into production. ## Regression Testing Challenges The reintroduction of a previously patched bug suggests potential gaps in the software development lifecycle and regression testing protocols. When a fix is undone by a subsequent update, it indicates that the codebase for the new build did not properly incorporate the previous patch, leading to the return of known software defects. ## Current Status Update With the deployment of build 16.0.5574.1006, the copy-paste functionality is reportedly restored for Excel 2016 users. Organizations currently experiencing the failure should ensure their systems are updated to this latest build to bypass the conflict. This release includes all previous security updates, ensuring that users remain protected against known vulnerabilities while regaining functionality. ## Software Maintenance Lessons This incident serves as a reminder of the complexities involved in maintaining legacy software versions like Excel 2016. Balancing critical security patches with feature stability requires rigorous verification processes. As users move forward, the focus remains on whether future updates will maintain this stability or if further regression issues will emerge. ## Sources covering this story - https://www.theregister.com/software/2026/11/05/microsoft-fixed-excel-2016-copy-paste-bug-then-reintroduced-it-now-its-fixed-again/5307782 — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._