The best tool to split large Outlook PST files is the Regain PST Splitter Tool. It offers three flexible splitting options, such as size, date, or even sorting emails by sender, recipient, or subject. All the critical email details like attachments, timestamps, and headers are maintained for integrity. It supports both UNICODE and ANSI formats, and is fully compatible with all versions of MS Outlook and Windows. Its easy-to-use interface makes Regain PST Splitter a fast, secure, and cost-effective way to handle large PST files efficiently.