Is it really impossible to break workbook protection?

Excel workbook protection is helpful, but it’s not something you should fully rely on for protecting sensitive data. In most cases, workbook and worksheet protection in Excel are designed to prevent accidental changes rather than provide strong security. People with enough knowledge or the right tools can sometimes bypass this protection. If you are dealing with personal data under GDPR, the safest approach is to remove any sensitive raw data from the file before sharing it. Even hidden sheets can potentially be accessed if someone tries hard enough. A better practice would be to keep the raw data in a separate secure file or system and only share the dashboards or anonymized results with your clients. So workbook protection can add a basic layer of control, but it shouldn’t be considered a guarantee that the data is completely safe.