Importing OST files to Yahoo Mail seemed nearly impossible for me. Manual methods, such as Outlook IMAP, worked only for small files, and Gmail, as a bridge, just made things more complicated. The real problem was with my orphaned OST file—it simply wouldn’t load. Then I tried OST to PST Converter, and it worked flawlessly. The tool lets you directly transfer OST emails, contacts, calendars, and attachments into Yahoo Mail. Even with a damaged OST file, it successfully recovered and migrated everything. It also gives the option to filter data so I could import only what I needed. Honestly, it feels far more reliable and efficient than spending hours on manual tricks.