Useful checks.
Explainable results.
We help people import, clean, compare and export everyday data with Excel, Google Sheets and small, explainable file workflows.
Who makes this
Column Harbor is an independent project by JHSOFT, a software business in South Korea. Its founder has 11 years of software development experience. This site is not affiliated with Microsoft or Google.
We focus on repeatable data problems: identifiers that lose zeros, dates that change meaning, hidden spaces, mismatched exports and file conversions that need clear rules. The checker is free and currently has no advertising or affiliate links.
How we produce a guide
- Start with a concrete problem and an original synthetic dataset.
- Check software behavior against official documentation and link to it.
- Check parser behavior, sample calculations and runnable code with representative inputs and failure cases, where applicable.
- State the limits, especially where an import choice depends on your data or Excel version.
Writing and software development are AI-assisted. We do not claim that AI output or automated tests replace hands-on testing in every target application. The guides distinguish our parser checks from behavior documented by the relevant software publisher. Data diagrams are illustrations of our examples, not screenshots of an application. Published and updated dates describe the article history, not continuous monitoring.
What the tool can tell you
It can show values present in a UTF-8 source file and flag selected patterns. It cannot restore overwritten values, validate every destination schema, scan every encoding or certify a file as safe. Formula-like prefixes are flagged as a precaution, but this is not a complete security scanner.
Corrections and feedback
Contact the owner on X (@sashimi_mong) with the page URL and a small synthetic example. Please do not send personal, financial or customer data. We may use reproducible, non-sensitive reports to improve the checks.