The yellow color in a cell indicates that conditional formatting has been applied to that cell. Conditional formatting is a feature in Excel that allows you to apply formatting to cells based on certain conditions.

In this case, it's possible that a

1. rule has been set up to highlight cells that contain a certain type of data or meet a certain criteria.
2. To check if this is the case, you can go to the "Home" tab in the Excel ribbon, click on "Conditional Formatting" and then select "Manage Rules".

This will show you all the rules that have been applied to your worksheet.

If you find a rule that is causing the yellow color, you can either modify or delete it to remove the formatting. If you don't see any rules that could be causing the issue, you can try selecting the yellow cell and then going to the "Conditional Formatting" menu again. This time, select "Clear Rules" and then "Clear Rules from Selected Cells". This should remove any conditional formatting that has been applied to the cell.

If neither of these solutions work, it's possible that there is some other type of formatting applied to the cell. To check this, select the yellow cell and then go to the "Home" tab" in the Excel ribbon. Look for the "Font" and "Alignment" sections and make sure that there are no formatting options selected that could be causing the yellow color.