Blue Triangles

Jack_Benson  wrote: ``how can they be deleted?``

I have not seen an answer to your question.

Presumably, you are talking about the triangle in the upper-left corner of some cells, shown below, that have a diamond "!" to the left when we select the cell, and that expand to a menu of options when we click the diamond.  See B2 and B6 below:

BTW, note that the color is indeed blue.  See below.

Excel calls this "background error checking".  But they are warnings, not errors. And 99% of the time, they are a misdirection.

For example, this warning arises because the SUM formulas in column B (shown in column C) do not reference all of the adjacent contiguous range of numbers.  Well, so what?!  That was my choice.

You can choose to click "Ignore Error" for each cell.

But IMHO, it is better to disable the feature altogether.

In my version of Excel, I get to the option by clicking File > Options > Formula.  The navigation might be different in your version.  Also, the appearance of the option might be different.

In any case, click next to "Enable background error checking" to remove the checkmark.

Also click "Reset Ignored Errors" to remove any warnings (upper-left triangles) that already exist.

Then click "OK" to commit the option.

Finally, note that the color of the warning indicator can be selected from the menu to the right of "Indicate errors using this color".  The default is green, at least in my version of Excel.  But presumably someone selected blue for your Excel.

No matter.  Just a note for everyone else's edification.