To convert multiple EML files to PST at once, you can use the SysInfo EML Converter Tool, which supports bulk conversion of single or multiple EML files without a size or count restriction. Start the software and select Select Files/Select Folder to add multiple EML files or an entire folder. After adding the files, preview important email details such as From, To, Subject, Date, email body, and attachments. Next, select PST as the saving format, choose a destination location, and click Convert to begin the process. The tool can also remove duplicate emails, preserve attachments, maintain the original folder hierarchy, apply date-based filters, and split large output PST files into smaller ones. These features make it easier to handle large EML collections while keeping email data organized during conversion.