If you're trying to figure out how to migrate Outlook OST to PST, the easiest and most reliable solution I've found is using the eSoftTools OST to PST Converter Software. Many Outlook users face situations where their OST file becomes inaccessible due to Exchange Server issues, account deletion, or corruption. Since Outlook doesn't provide a direct option to migrate OST data to PST, a professional tool like eSoftTools makes the process effortless. With this software, you can quickly load your OST file, preview all mailbox data such as emails, attachments, contacts, calendars, and journals, and then export everything directly to a new PST file. The best part is that it maintains the original folder structure and email formatting throughout the conversion.
The eSoftTools OST to PST Converter also supports conversion to multiple formats including PST, EML, MBOX, MSG, and HTML, giving you flexibility depending on your needs. It works perfectly with all versions of Outlook (2021, 2019, 2016, 2013, and older) and supports both healthy and corrupted OST files. Its user-friendly interface makes it suitable for both technical and non-technical users. Additionally, the tool comes with a free demo version, allowing you to migrate a limited number of items from OST to PST to test its performance before purchasing.