graphs in excel - bar chart changes from nice thick bars (Vertical) skinny lines. 2 images attached showing how 1 chart changed.

Dear Paul Gailiunas,

Welcome to the Microsoft Q&A forum.

Thank you for sharing the attachments. Based on the charts provided, I understand that you are seeing two different chart views in Excel, and the chart appears to automatically change its appearance. I would like to clarify a few points to help identify the cause.

From your screenshots, it seems that the two charts are not displaying the same underlying data or axis configuration. For example:

• The vertical axis scales are different: one chart goes up to 500,000, while the other only goes up to 100,000.
• The data series colors also differ. The original chart shows multiple colors, whereas the thinner chart displays only two, which suggests fewer data series.
• The x‑axis labels are not the same either. One chart shows only “Jan,” while the other includes specific dates such as 22/12, 29/12, and so on.

These differences typically indicate that the chart may not be referencing the same data range, or that the data itself has been modified. To investigate this further, could you please check the Version History of the Excel file to see whether any data or chart ranges were updated by someone else?

Refer article: View or restore version history of a workbook - Microsoft Support

Once you have this information, feel free to share it here and I will be happy to assist you further.

Looking forward to hearing from you.

In Excel, a bar/column chart can appear to change from thick bars to very thin “lines” when the chart type or series layout is altered. This usually happens if the chart is switched to a different subtype (for example, from a clustered bar/column to a stacked or 100% stacked type, or to a different chart type entirely) or when a combo chart is applied.

To restore the thick vertical bars:

1. Select the chart.
2. On the ribbon, go to Chart Tools → Design → Change Chart Type.
3. In the All Charts tab, choose Column (or Bar) and select a standard Clustered Column (or Clustered Bar) chart subtype.
4. Apply the change so all series use that same bar/column subtype.

If only one series was changed previously (for example, when using a combo chart), ensure that each series is set back to the same clustered bar/column type so they all render as thick bars again.

If Excel 2013 or later is in use and only one series was intended to be different, note that changing the chart type from the ribbon now affects all series at once. To mix chart types, use a Combo chart instead and explicitly set each series’ type there.

References:

• Available chart types in Office
• Discontinued features and changed functionality in Excel 2013