An Excel file opens in Calc, but a notice about an unsupported chart replaces the waterfall chart. That alone is no reason to delete the object or repair the file. This guide is for small offices and anyone exchanging XLSX files between Excel and LibreOffice: displaying, editing and preserving a chart when saving are three different capabilities.
What changed in 26.8
On 17 September 2026, The Document Foundation explained that LibreOffice 26.8 recognises certain modern OOXML charts and preserves their definitions when saving, even though it cannot display or edit them. Examples include waterfall, funnel, Pareto, box-and-whisker and treemap charts. There is an important exception: regional map charts. The developer says their type survives, but much of their geographical content does not. This is a compatibility boundary, not a promise that every workbook will survive unchanged. [1]
Preparation: preserve an original and a reference
You need an untouched original, a working copy and access to the application that displays the chart correctly. Record the exact application versions, file format and chart type. If necessary, ask the sender for a PDF reference and the expected key values. Do not upload confidential workbooks to public converters or enable macros and external data connections for this diagnosis. In a managed workplace, involve IT.
A six-step XLSX check
- Protect the original. Copy the XLSX file into a separate checking folder. Give the original, working copy and return copy distinct names. First view the original in the application that already works and record the chart title, axes, legend and important values.
- Narrow down the symptom. Open the working copy in LibreOffice 26.8. Record the exact message and worksheet. Check whether only the chart is affected or whether data and formulas also differ. A placeholder for one of the listed types may fit the documented limitation; an empty area alone does not prove it.
- Treat maps separately. If the workbook contains a regional map, do not rely on a lossless round trip. Keep using the working source application for content changes. If only a visual reference is needed, request a PDF created and checked there. [1]
- Create a return copy. For the other affected chart types, initially leave the chart and its source data unchanged. Use File → Save As to create a new XLSX copy and check the selected format. Read format warnings; do not experiment by converting to ODS or CSV. LibreOffice Help explains how to select a Microsoft Office format. [2]
- Check the round trip. Close the saved copy and open that exact file in the original application. Compare its chart, labels and numbers with the original. If you intend to edit cells, run a separate test on another copy afterwards: an unchanged round trip does not prove that later edits will be reflected correctly in the chart.
- Record the decision. Note the filename, both application versions and the result: passed, different or untested. If there are differences, do not send the return copy as an approved version; continue with the untouched original. Without access to the target application, approval remains pending.
Choose the right way to share
For further chart editing, the working source application is the more reliable starting point. A PDF created there can help with viewing, but replaces neither formulas nor editable data. Exporting a PDF from an application that cannot display the chart is not a substitute. For future joint editing, agree on a simpler chart type tested in both applications, in a new version and with the document owner's consent. ODF is LibreOffice's native format, not an automatic repair for an imported Excel chart. [3]
When has the check passed?
Only the specific exchange has passed: the original is untouched, the return copy has been opened in the target application, the chart and key values are correct, and no unexplained warnings remain. File size or a successful save is not enough. When reporting a problem, start with versions, file format and chart type; reinstalling, resetting a profile or disabling security features are not useful first steps here.
Date and sources
As of 25 September 2026. Source-based guidance with an editorially derived checking procedure, not a hands-on LibreOffice/Excel test. The occasion is the developer's 17 September article, not a demonstrated search surge. No affiliate links. Source [3] covers general file formats in version 25.2, not the new chart-preservation behaviour in 26.8.