MICROSOFT says its September 2026 Office update caused Excel formula-calculation problems and prevented some users from copying and pasting data. Although the issue was initially reported as affecting Excel 2016, user reports indicated that other editions were also affected. Microsoft has since issued fixes for several versions: Office LTSC 2024 is updated in build 17932.21000, Office LTSC 2021 in build 14334.20918, and Office LTSC 2019 in build 10417.20208. Excel 2016 users are instructed to manually install hotfix KB5002665 and restart the application.
A remaining problem affects Office LTSC 2019 workbooks containing conditional formatting: transfer operations can still fail. Microsoft’s temporary workaround is to use Excel’s “Paste Special” option after copying, selecting the required content type, such as formulas, values or number formats. The article also says that “Paste Link” may bypass the conditional-formatting restriction while a permanent fix is developed. Users of the affected editions should install the specified updates, while 2019 users working with conditional formatting may need to use the workaround.