How to convert MBOX to PST: 4 methods compared

Before you start: what a good conversion keeps

Whatever method you choose, check the result against this list. A good MBOX to PST conversion keeps:

• Your folder structure. Each mailbox (or Gmail label) should become an Outlook folder, not one giant Inbox.
• Attachments and inline images, including pictures embedded in HTML newsletters and signatures.
• Dates, senders and recipients, so sorting and searching work as before.
• Read and flagged status, so you don’t end up with 40,000 “unread” messages.
• Accented and non-Latin text in subjects and bodies, without garbled characters.

It also helps to know how big your mailbox is. A few hundred megabytes is easy with any method; 20 GB or more rules out some of them. If you are unsure what MBOX and PST actually are, our explainer MBOX vs PST covers the differences.

Method 1: Thunderbird as a bridge, via an IMAP account (free)

This is the classic do-it-yourself route. Thunderbird can read MBOX files, and Outlook can read any IMAP mailbox. By connecting the same IMAP account to both apps, you can use the mail server as a go-between.

1. Install Thunderbird and the free ImportExportTools NG add-on (from the Thunderbird add-ons site).
2. Right-click Local Folders and use ImportExportTools NG → Import mbox file to bring in your MBOX files.
3. Add an IMAP account to Thunderbird, for example an Outlook.com or Microsoft 365 mailbox you also use in Outlook.
4. Create a folder in that IMAP account and drag (copy) the imported messages into it. Thunderbird uploads them to the server.
5. Open Outlook, connected to the same account, and wait for the folder to sync. Then export it to a PST from the Import/Export wizard (in classic Outlook: File → Open & Export → Import/Export → Export to a file), or simply keep the mail in the mailbox.

Use it when the mailbox is small (up to a few gigabytes), you are comfortable with Thunderbird, and you have time to babysit the copy.

Method 2: A desktop converter app

Many companies sell Windows programs that read MBOX files and write a PST directly. You install the app, point it at your files, choose options and let it run on your own computer.

If you go this way, download only from the vendor’s own website, read independent reviews, and test the trial with a small mailbox that has attachments, accented characters and a few subfolders. Check the result in Outlook before buying a licence.

Use it when you must keep the data on your own machine (for example by company policy), you have a Windows PC available, and you expect to convert mail regularly.

Method 3: Skip MBOX: sync the account into Outlook and export

If the original mailbox still exists on a server (a live Gmail, Yahoo or company account), you may not need the MBOX file at all. Add the account to Outlook over IMAP, let Outlook download everything, then export it to a PST.

1. In Outlook, add the account (File → Add Account in classic Outlook). For Gmail, make sure IMAP is enabled in Gmail’s settings; Outlook signs in through Google’s own login page.
2. Wait until every folder has finished downloading. For large mailboxes this can take hours, sometimes days.
3. Open the Import/Export wizard, choose Export to a file → Outlook Data File (.pst), select the account’s top folder, tick Include subfolders and save.

Use it when you still have access to the old account, it is moderately sized, and it isn’t Gmail with heavy label use.

Method 4: An online MBOX to PST converter

An online converter does the work on a server. You upload your MBOX files in the browser and download a finished PST. MoveMyInbox is one of these services; here is what the process looks like with it:

1. Create an account and drag your MBOX files or folders onto the upload area.
2. See the price, a one-time amount based on the total size (see pricing), and pay with Stripe.
3. The conversion runs in the cloud, typically in minutes.
4. Download one Unicode PST and open it in Outlook.

Folders are kept: one Outlook folder per MBOX file, or, for Google Takeout, Gmail labels mapped to folders such as Inbox, Sent Items and your own labels as nested folders. Attachments, inline images, read and flagged status and any character set come along too.

Before uploading mail to any online service, read how it handles your data. At MoveMyInbox, uploads are deleted as soon as the PST is ready, the PST is deleted after 7 days, files are encrypted in transit and at rest, and no person reads your mail. Details are on our security page.

Side-by-side comparison

Which method should you choose?

You have a Google Takeout file

The Takeout MBOX is one large file with every label recorded in each message. An online converter that understands Gmail labels gives you real Outlook folders without duplicates. The free Thunderbird route works but loses the label structure unless you sort messages by hand. Our article on moving Gmail to Outlook goes deeper.

You are leaving Thunderbird or Apple Mail

Your mailboxes are already separate MBOX files, one per folder, so most methods keep the structure. See Thunderbird to Outlook and Apple Mail to Outlook for the export steps.

The old account is still active

Try Method 3 first. It costs nothing and you may not need any MBOX file at all.

The archive is very large

Above roughly 10 GB, IMAP-based methods become painfully slow. Use a converter, and read PST size limits explained before creating one enormous file.

After converting: check the result

Whichever route you took, spend five minutes checking the PST before you delete anything:

1. Open the PST in Outlook and compare folder names and message counts with the original.
2. Open a few old messages with attachments and make sure the files open.
3. Search for a word with accents or a name you know is in there.
4. Keep the original MBOX files until you are happy. Storage is cheap; lost mail isn’t.

Then decide whether to keep the PST as a separate archive or import it into your mailbox. The PST import guide explains both options.