MBOX to PST — move Thunderbird or Gmail mail into Outlook
Convert an .mbox file to an Outlook .pst in your browser — Thunderbird folders (the file next to the .msf), a Gmail Takeout export or Apple Mail. Messages, attachments and pictures kept, nothing uploaded, no limit.
About this conversion
Outlook cannot read an mbox, and that is the format Thunderbird keeps its folders in, Gmail exports through Google Takeout and Apple Mail exports to — so moving to Outlook usually means a paid desktop converter. This page reads the mbox and writes a .pst that Outlook opens or imports directly. Each message keeps its sender, recipients, date, HTML body and attachments, and pictures that sit inside the text stay inside the text rather than turning into loose attachments.
Just want to look inside it?
The same tool without converting anything: open a .mbox file and read it.
You are not locked into PST
The file is parsed once and stays open, so the format is picked at the end rather than the beginning: the same .mbox 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
- I have an .msf file — is that the mailbox?
- No. In a Thunderbird profile every folder is two files: the mail itself, in a file with no extension (“Inbox”, “Sent”), and an .msf next to it, which is only Thunderbird’s index. Convert the file without the extension — it is an mbox. You will find them under Mail or ImapMail in the profile folder (Help › Troubleshooting Information › Profile Folder in Thunderbird); you can also choose the whole folder here. For IMAP accounts Thunderbird keeps full messages only for folders it syncs for offline use.
- How do I get my Gmail into Outlook?
- Export the mail with Google Takeout (takeout.google.com, Mail only). Google sends a .zip; drop it here as it is, or the .mbox inside it, and save the result as .pst.
- Which Outlook can open the result?
- Outlook for Windows, through Open Outlook Data File or Import/Export. The file is in the Unicode .pst format that every Outlook since 2003 reads, and we check our output with Microsoft's own Inbox Repair Tool (SCANPST) and in Outlook itself. The new Outlook for Windows opens .pst files only with a Microsoft 365 subscription.
- Can I convert only some of the messages?
- Yes. Search or filter first — by year, sender or attachment — and only the messages that are listed go into the .pst.
- Are duplicates copied twice?
- Only if you want them. Tick “hide duplicates” before saving and each message goes in once.