Learn VBA Macros with Validation and Error Handling
Keep procedures focused
Use explicit variable declarations and descriptive names. Separate input checks, transformation logic, and output formatting so each part can be reviewed. Avoid relying on whichever workbook or sheet happens to be active; qualify references to the intended workbook and worksheet.
Validate and recover
Check that required sheets, columns, and values exist before changing anything. Handle expected errors with a clear message and a predictable exit path. Do not hide failures with blanket error suppression. Where a process updates important files, work from a copy, preserve an original, and make partial completion visible.
Test macros responsibly
Use synthetic data and a disposable workbook while developing. Review the code source, macro settings, signatures, and organization policy before enabling macros. Never assume a file or macro is safe merely because it arrived in an Office document.
Practice task
Write a macro that checks for a named input sheet, validates required columns, formats a copy of a small synthetic table, and reports missing values without overwriting the source.