Export OST to PST Through a Working Outlook Profile Step by Step
If your Outlook profile still opens the mailbox, this is the whole conversion - one built-in wizard, about ten careful minutes, zero cost. Most failed exports fail for one of three small reasons, and each step below names the one it prevents.
✍️ Technical Anshu📧 Microsoft Outlook⏱️ 10 minute job
🎥 Watch the video to see the export wizard run live from start to finished PST
The Import and Export wizard has been inside Outlook for decades, and it is still the only fully free, unlimited way to turn OST content into a PST. It copies - never moves - whatever you select: mail, calendar, contacts and tasks. Do the steps in this order; the preparation in Step 1 is what separates a complete PST from a quietly incomplete one.
Import and Export Wizard - Choose an action to perform_ □ X
The three choices that decide everything - top of the mailbox, subfolders ticked, password empty. Most incomplete exports missed the first two
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Step 1 - Finish the Sync Before You Export Anything
The export can only contain what the OST actually holds. If Outlook has been set to keep only the last few months of mail on this PC, the older mail was never downloaded - and cannot be exported until it is.
Go to File > Account Settings > Account Settings, open your account and choose Change
Drag the Download email from the past slider to All
Restart Outlook and watch the status bar until it says the folders are up to date - on a big mailbox this can take real time, so leave it plugged in and syncing
Only then start the export. This one step is the difference between years of mail in the PST and a polite-looking file missing everything old
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Step 2 - Run the Export Wizard in This Exact Order
File > Open & Export > Import/Export
Choose Export to a file, then Outlook Data File (.pst)
Select the very top line of your mailbox - your account name, not the Inbox - and tick Include subfolders
Choose where the PST goes. A different drive from the OST is safer; a plain name like mailbox-backup-2026.pst beats the default
If Outlook warns the file already exists, you are exporting over an earlier try - pick a fresh name rather than overwriting
Click Finish and let it run to the end. Do not close Outlook mid-export
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Step 3 - Walk Past the Password Screen Without Falling In
At the end, the wizard offers to password-protect the new PST. Leave both boxes empty. A PST password is old, weak protection - and if you forget it, there is no official recovery at all. Your own backup becomes the one file you can never open. If the mail is genuinely sensitive, protect the drive it sits on instead, with BitLocker or an encrypted folder - protection you can actually manage.
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Step 4 - Very Large Mailbox - Split the Export by Year
One giant PST is a fragile thing: slow to open, painful to copy, and a single corruption touches everything. For mailboxes in the tens of gigabytes, run the wizard several times instead - once per year or per big folder, using the Filter button on the folder screen to limit by received date. Several medium PST files are easier to verify, store and restore than one monster.
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Step 5 - Verify the PST Before You Trust It
Use File > Open & Export > Open Outlook Data File and open the new PST itself
Check three things: the oldest folder you care about, the newest mail, and one message with a large attachment
Compare a folder count or two with the live mailbox - they should match
Close the file again (right-click its name, then Close) once verified. Only now is the conversion actually done
🔴 Export means copy. Nothing in this process removes mail from your mailbox or shrinks the OST. If your real goal was freeing space, that is a different job - archiving - and deleting the OST afterwards only works while the account is healthy enough to rebuild it.
🎥 Watch the Complete Process in the Video
The wizard is easier to follow once you have seen it run - the video does the complete export on screen, sync check included.
A few minutes for a small mailbox, and easily an hour or more for tens of gigabytes - the sync in Step 1 is usually the slow part, not the export. Start it when the PC can sit plugged in and untouched.
The exported PST is much smaller than my OST - is something wrong
Not automatically. OSTs carry indexes, views and empty space, so a PST is often noticeably smaller while holding the same items. The real test is Step 5: open the PST and compare folder counts and sample messages, not file sizes.
Can I export only one folder instead of the whole mailbox
Yes. In the wizard, select just that folder instead of the top of the mailbox. Leave Include subfolders ticked if it has children. This is also the cleanest way to rescue a single local folder, like an old calendar, before a PC move.
This guide is based on the Convert OST to PST Free video by Technical Anshu • Stuck on any step, ask in the video comments and the community will help you 🙏