To restore inaccessible MBOX file data, you can use SysInfo MBOX Converter. This tool is designed to recover data from damaged or corrupted MBOX files. First, download and install the SysInfo MBOX Converter on your Windows or Mac computer. Once the software is installed, open it and add the inaccessible MBOX file by clicking on the "Add Files" button.

The tool will then scan the selected MBOX file and preview its contents in a tree structure, allowing you to see all the emails and attachments. If the MBOX file is corrupted or inaccessible, the tool will try to repair and restore the data. After the scan is complete and the data is recovered, you can save the restored emails in various formats such as PST, EML, PDF, or MSG, ensuring you can access the data in your preferred email client.
Read more: https://www.sysinfotools.com/recovery/mbox-converter.php