If your Outlook PST file is becoming too large, splitting it is a smart strategy to avoid data corruption and boost Outlook's performance. One tool I’ve found really helpful is
Stellar Splitter for Outlook.
This professional-grade utility allows you to split large PST files safely and efficiently—whether by size, date, email ID, or folder.
Stellar also provides a free demo version, so you can give it a whirl before making a commitment. It’s definitely a safe and reliable option if you’re grappling with oversized Outlook data files.