OST to PDF — save messages from an offline Outlook file
Open an .ost file in the browser and save its messages as PDF, with sender, date and subject intact.
About this conversion
An .ost belongs to an account that may no longer exist, and Outlook will not reopen it without one. Saving a message as PDF cuts that dependency: the message becomes a document that opens anywhere, keeps its sender, date and text, and can be filed or sent on without explaining what an .ost is.
Just want to look inside it?
The same tool without converting anything: open a .ost file and read it.
You are not locked into PDF
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, MBOX, 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.