Convert MBOX to Outlook PST.
Gmail, Thunderbird, and Apple Mail all hand you a .mbox. Outlook will not open one. This converts your archive into a real Unicode .pst — on your iPhone, iPad, or Mac, with your folders and labels intact, and without a single message leaving the device.
100% on-device | .mbox · Takeout .zip / .tgz | Unicode PST | No size limit | Verified manifest
MBOX is what almost everything exports to. Google Takeout writes it, Thunderbird stores in it, and Apple Mail's Export Mailbox produces it. Outlook reads none of it. That gap is where mailboxes go to sit for years — downloaded, backed up, and completely unusable in the one app the person actually needs them in.
This app closes the gap on the device you already have. It writes a genuine Unicode PST — the modern Outlook format, not the old ANSI one — built to open cleanly in Outlook, and in the forensic and e-discovery readers that legal and IT teams rely on.
Size is the usual reason a conversion fails, and it is what this app was built around. A full Google Takeout "All mail" export opens on a phone, and a single malformed message is counted and stepped over instead of ending the run.
The part that matters most is that it tells you the truth afterwards. Every conversion ends in a manifest: messages found in the source, messages written into the PST, messages skipped, and duplicates skipped. If anything was skipped the manifest says so rather than reporting a clean run — and if a conversion cannot finish, the partial PST is deleted instead of being left behind to look like a result.
The archive, however it reached you.
Takeout does not hand you a tidy .mbox. It hands you an archive, sometimes split, sometimes renamed. All of that is handled for you.
Takeout .zip and .tgz
Both download formats, unwrapped in place — including a Takeout split across several downloads.
Renamed archives
A Takeout downloaded as mail.zip and renamed mail.mbox is still recognised for what it actually is, whatever the extension says.
Apple Mail exports
Mailbox ▸ Export Mailbox produces a .mbox that most converters refuse to open. This one opens it.
No silent wrong answers
An archive that cannot be read correctly is refused outright rather than converted into a result you cannot trust.
How to convert an MBOX file to PST.
Open your archive
Pick a .mbox, or the Google Takeout .zip or .tgz exactly as it downloaded, from the Files app, a download, or the share sheet. Nothing is copied and nothing is uploaded.
See the folder tree first
The archive is indexed in place and you get the folder tree the PST will have, with a message count on every folder — before you convert, not after.
Choose what goes in and how
Untick Spam, Trash, or an old year and the total updates live. Keep the Gmail folders, or file everything by year or by sender domain instead.
Convert and read the manifest
The PST is written on the device, then the manifest reports found, written, skipped, and duplicates so you know exactly what you are handing on.
MBOX in, Unicode PST out.
The standard mail archive written by Google Takeout, Thunderbird, and Apple Mail's Export Mailbox — including Apple Mail's directory-style .mbox package.
Google Takeout's two download formats, opened on the device exactly as they downloaded.
A Unicode PST — the modern Outlook format, with attachments, read state, and a real folder tree.
Built for archives that are too big to convert anywhere else.
No Size Limit
The archives that make desktop converters give up open here, on a phone, without a ceiling to work around.
Real Unicode PST
The modern Outlook format, not the legacy ANSI one — so there is no 2 GB ceiling and no compatibility surprise on the far side.
Gmail Labels Become Folders
A mailbox labelled in Turkish, German, or Japanese produces a correct folder tree, not a screenful of garbled characters.
Three Ways to Organise
Keep the Gmail folders, put a folder per year under Archive, or file everything by sender domain — the tree updates before you commit to it.
Pick Folders Before Converting
Every folder is listed with its message count. Untick the ones you do not want and the included total recalculates on the spot.
Read State Preserved
Read and unread are carried across, derived from the Status header and the Gmail labels — which are matched in every language the export might use.
Duplicate Detection
Takeout writes the same mail once for every label it carries. Those repeats are detected and counted rather than multiplied into your PST.
Verified Manifest
Found, written, skipped, duplicates. A run with anything skipped is reported as such — the app will not call an incomplete transfer clean.
Nothing Half-Written
If a conversion cannot complete, the partial PST is removed. You are never left with a file that looks like a result and is not one.
Survives Bad Messages
A malformed message is caught, counted, and stepped over. One broken mail in a 200,000-message archive does not end the run.
Readable by Forensic Tools
The PST opens in the e-discovery and forensic readers legal and IT teams use, not only in Outlook.
iPhone, iPad, and Mac
One app across all three. The PST it produces is also kept out of iCloud backup, so a big conversion does not quietly inflate yours.
Indexing, unwrapping, conversion, and verification all run locally. Your mail is never uploaded to a conversion service, and no network is needed at any point.
The archive is indexed in place — not copied, not modified. The PST is written separately, so the original Takeout or export stays exactly as it was.
The manifest counts what went in and what came out. If messages were skipped, it says so, with the number, instead of showing a green tick.
- Moving a Google Takeout mail export into Outlook without uploading a mailbox to a conversion website.
- Converting an archive far larger than desktop converters manage — the engine is built for tens of gigabytes.
- Migrating a Thunderbird or Apple Mail mailbox to Outlook when there is no Windows machine to hand.
- Producing a PST for legal, compliance, or e-discovery hand-off, with a manifest that documents the transfer.
- Turning years of Gmail labels into a real Outlook folder tree instead of one undifferentiated inbox.
- Re-filing a folderless archive by year or by sender so an old mailbox is navigable again.
- Handling a Takeout that arrived split across several archives, or downloaded as .tgz rather than .zip.
Download it and open your first MBOX archive straight away. There is no account to create, and nothing about your files leaves the device.
Converting MBOX to PST.
What is an MBOX file?
MBOX is a plain-text mail archive format that stores messages one after another in a single file. Google Takeout exports it, Thunderbird stores mail in it, and Apple Mail's Export Mailbox produces it. Outlook does not read it, which is why a conversion is needed.
Can I convert MBOX to PST without Outlook installed?
Yes. The PST is written from scratch on your device. Outlook is not involved in producing it, and is only needed at the other end if that is where you intend to import the file.
Does it handle a Google Takeout download directly?
Yes. Give it the .zip or the .tgz exactly as it downloaded and it unwraps the archive itself, including a split Takeout that arrives as a zip of zips. You do not need to extract anything first.
How large an archive can it handle?
There is no fixed limit. A full Google Takeout "All mail" export opens on a phone, not just on a desktop.
Will my Gmail labels survive the conversion?
Yes. Labels become a real Outlook folder tree, and labels in any language come through correctly rather than as garbled text.
What if my archive has no folders at all?
Choose how it should be organised. You can file everything by year, producing a folder per year under Archive, or by sender domain — and you see the resulting tree before converting.
Can I leave out Spam and Trash?
Yes. Every folder is listed with its message count and you can untick any of them. The included message total updates immediately so you know what you are converting.
Is it a Unicode PST or the old ANSI format?
Unicode, the modern Outlook format. That matters because the older ANSI PST carries a 2 GB ceiling that a real mail archive passes quickly.
How do I know every message made it?
The conversion ends in a manifest: how many messages were found in the source, how many were written to the PST, how many were skipped, and how many duplicates were dropped. A run with skips is flagged rather than reported as clean.
Why are duplicates skipped?
Google Takeout repeats the same message once per label it carries, so a mail with three labels appears three times in the export. Those repeats are detected and counted on the manifest instead of being written three times.
Is my mail uploaded anywhere?
No. Online MBOX to PST converters require uploading the entire mailbox to someone else's server. Everything here happens on your iPhone, iPad, or Mac, with no network involved.
Can it convert a PST back to MBOX?
Not this app — that is the other direction, and it is covered by PST to MBOX Converter. This one writes PST from an MBOX archive.
Can I read my messages in the app?
No. This is a converter, not a mail reader: it shows the folder tree and message counts so you can decide what to convert. To open and read messages inside a .mbox, use MBOX Viewer instead.
What people open next.
Every Rush tool runs entirely on your device. These are the ones that come up in the same job as this one.
- MBOX Viewer.mboxRead the messages inside the archive first — this converter shows counts, not content.
- PST to MBOX Converter.pst → .mboxThe opposite direction, for when a PST needs to become MBOX instead.
- OLM Converter.olm → .mboxIf the mail started as an Outlook for Mac .olm, turn it into MBOX first.
- PST Viewer.pst · .ostOpen the PST you produced and confirm the folder tree came through intact.
Get your MBOX archive into Outlook.
A real Unicode PST, folders and labels intact, a manifest that tells you the truth, and no size limit — on iPhone, iPad, and Mac, 100% offline.
MBOX to PST Converter is an independent utility from Rush Tools. Outlook, Gmail, Google Takeout, Thunderbird, and Apple Mail are named only to describe file compatibility and migration sources; this app is not affiliated with or endorsed by their owners.