An error shown in a report total may originate several formulas earlier. Replacing the total with zero can make the sheet look finished while leaving the missing or invalid input unresolved. Follow the dependency before deciding what the final cell should display.

Preserve the affected workbook and note the exact error cell, formula and expected meaning. If the workbook belongs to another person, establish which input source they consider authoritative before making corrections.

Follow the error-producing precedent

Select the error cell and choose Tools, Detective, Trace Error. LibreOffice draws arrows to precedent cells responsible for the error value. Use those arrows to inspect the referenced inputs and intermediate calculations; they are a route through the sheet, not an instruction to delete the cells they identify.

A disposable example makes the distinction clear. Put 12 in A1 and 0 in A2, enter =A1/A2 in B1, then =B1*2 in C1. The final error in C1 originates from the division in B1. Editing C1's multiplication will not resolve the zero denominator.

Inspect B1 and its two inputs. If the intended denominator is three, correcting A2 produces four in B1 and eight in C1. Those numbers can be checked independently. If zero actually means that no measurement exists yet, inventing a denominator of three would conceal the real problem.

Correct meaning, then verify propagation

For the real workbook, compare the suspect input with its source record. A missing quantity, text in a numeric field and an unavailable linked value require different corrections. Keep the observed error separate from any assumption about why the source supplied it.

After an authorised correction, inspect both the immediate formula and the downstream report result. Check a neighbouring unaffected record as well, particularly after changing a shared input or reference.

If a blank or special label is the agreed way to represent unavailable results, document that rule only after identifying the cause. Error handling should communicate a known condition. It should not turn every unresolved calculation into a reassuring-looking number. Finally, remember that an incorrect formula can also return an ordinary number; error tracing does not validate all workbook logic.

Reference: LibreOffice documentation.