Administrating Microsoft Exchange or Microsoft 365 inevitably leads to situations where a user’s mailbox is deleted, yet access to its data remains necessary. In such cases, the native Microsoft tools may fall short, leaving only an Outlook OST file as a resource. This review evaluates Stellar Converter for OST, assessing its performance in realistic scenarios where administrators might use it. The software is designed to extract data from Outlook OST files, converting it into formats like PST or exporting it directly to Microsoft 365 or Exchange Server, even when the original mailbox is unavailable. It is particularly useful for deleted or disabled Microsoft 365 mailboxes, orphaned OST files, and legal or compliance recovery scenarios.
To ensure a realistic evaluation, a lab environment was created, simulating common enterprise support cases with cached Exchange Mode enabled and OST files generated locally. The installation process was quick and straightforward, leading directly to the OST selection screen. During testing, the scans were successful across various file sizes without crashes or application hangs, and the system’s CPU and memory usage remained stable. The tool presented a complete mailbox tree after scanning, with data that matched the expectations of a live mailbox.
The software’s export capabilities were tested by exporting mailboxes to PST and importing them into Outlook 2019 and Microsoft 365 Apps without errors. Direct export to Microsoft 365 was also successful, with no duplicate items. Features like date-range filtering and folder-level export proved useful for compliance requests. Throughout repeated scans and exports, the software demonstrated stability and predictable performance, crucial for administrators working under pressure.
From a security standpoint, all processing occurs locally, and OST files are accessed in read-only mode, aligning with enterprise security standards. However, it is important to note that exporting requires a paid license. Overall, Stellar Converter for OST is rated 4.6 out of 5, proving to be a reliable tool for administrators facing OST file conversion challenges.
