I was searching for a reliable way to open OST file without Outlook, mainly to check whether my emails and attachments were still intact after a profile corruption. Manual methods didn’t help, but the SysInfo OST Viewer Tool turned out to be a solid option. One feature I really liked is its detailed preview panel. It doesn’t just show folder names; it allows you to open individual emails, read message bodies, view attachments, and inspect other Outlook items like notes and calendars. This is extremely helpful when you want to verify data before converting or recovering it. Many tools only offer limited visibility, but here the mailbox structure stays intact, making navigation easy even for large OST files. If your goal is to open OST file without Outlook and thoroughly analyze the mailbox content before taking the next step, this feature alone makes the tool worth considering.