How to handle empty cells in CSV data

Step-by-step approach

Generate a missing-value report and identify which columns are incomplete.
Determine whether a blank means unknown, not applicable or accidentally omitted.
Avoid using 0 for missing monetary values unless it genuinely represents zero.
Fill appropriate fields with a documented placeholder using the fill tool.
Keep a copy of raw data and record the assumptions used for the replacement.

Try the matching tool

Open Missing Value Report to work on a local copy. Review the result before importing it elsewhere.

What this does not solve

Browser tools can validate known structures and transform available data, but cannot restore deleted or corrupted bytes, infer unknown business facts, or guarantee that a target system will import every field as intended.