I have an old OST file that I need to access, but Outlook is no longer installed on the system and the Exchange Server account associated with the file is no longer available. The OST contains important historical emails and attachments, so I’m trying to find a way to recover the mailbox data without restoring the original Outlook profile or reconnecting to the Exchange environment.

I’m mainly concerned about preserving the data properly during the conversion. The mailbox contains multiple folders and subfolders, along with emails, contacts, calendars, tasks, notes, and attachments. I’d like the recovered data to retain its original organization rather than having to manually sort everything after the conversion.

From what I’ve been researching, some dedicated tools can access OST files directly without requiring an Outlook installation or an active Exchange connection. This seems particularly useful for orphaned or old OST files where the original account is no longer accessible. I’m considering whether I can convert OST to PST locally and then open the resulting PST whenever I need to review the historical mailbox data.

Another feature I’m looking for is a preview option. Before creating the final PST, I’d prefer to check the mailbox folders and individual emails to confirm that the required information and attachments are actually present. Date filtering and duplicate removal would also be useful if the OST contains a large amount of historical data.

During my research, I came across the SysInfo OST to PST Converter. Its product information says it can access healthy, orphaned, password-protected, and oversized OST files without Outlook or an active live Exchange connection. It also supports previewing OST data and maintaining folder hierarchy, timestamps, metadata, and attachments.

I’m also comparing different OST to PST converter software options because I may eventually need to process multiple OST files. Batch processing, date-range filtering, duplicate removal, attachment handling, and the ability to skip previous exports could make the process easier when working with large mailbox archives.

Has anyone converted an OST file without having Outlook or Exchange Server available? I’d like to know which approach you used and whether the resulting PST retained the original folder structure, emails, metadata, and attachments correctly.