plainfolder → Mail → OST → MBOX
OST to MBOX — rescue an offline Outlook file into a readable format
Turn an .ost file into an mbox archive that Thunderbird and Apple Mail can import, without the original account.
No server processing
No account
No daily limits
About this conversion
An .ost is the copy Outlook keeps on disk, and it is useless once the account behind it is gone. As mbox the same messages become ordinary mail again — importable, searchable, and not tied to one program.
Just want to look inside it?
The same tool without converting anything: open a .ost file and read it.
You are not locked into MBOX
The file is parsed once and stays open, so the format is picked at the end rather than the beginning: the same .ost can leave here as CSV, XLSX, ZIP, EML, PDF, HTML, TXT or JSON. Before that you can search it by subject or address, filter by year, sender and attachment type, mark the duplicates and look through the archive overview.
Questions
- Do I need the original account?
- No. The messages are read out of the file itself.
- Which programs will open the result?
- Thunderbird and Apple Mail both import mbox directly. Outlook does not read mbox at all, so if the mail has to end up there, convert to separate .eml files instead and drag them into an Outlook folder.