OST to CSV — read an offline Outlook file as a table
Open an .ost file without Outlook and export the messages as a CSV table. The file stays on your computer.
About this conversion
An .ost is the offline copy Outlook keeps on disk, and it is usually all that remains once the account behind it is gone. Turned into a table it answers the questions people actually have about such a file: how many messages are in there, from whom, over which years, and which of them carry attachments — before deciding what is worth pulling out.
Just want to look inside it?
The same tool without converting anything: open a .ost file and read it.
You are not locked into CSV
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 XLSX, ZIP, EML, MBOX, 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 versions are supported?
- Files from Outlook 2003 onwards, including the newer 4 KB format used since Outlook 2013.