Written by Jennifer Walsh. Reviewed for technical accuracy by Shubham Dixit, Independent Expert in Email Forensics and Data File Conversion. Updated 18 September 2026.
Shubham is an independent external reviewer and not an employee of PCDOTS.
Quick answer. A PST is Outlook’s local mailbox file, and IMAP is an account kept on a server. To migrate Outlook PST to an IMAP server, you add the IMAP account in classic Outlook, open the PST, then drag its folders into the account. Outlook uploads them. To go the other way and back up an IMAP account to a PST, you use Export to a file. A tool does either in bulk.
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What does migrating a PST to IMAP mean?
A PST is Outlook’s local mailbox file, sitting on your computer. An IMAP account keeps your mail on a server, so it syncs to every device. IMAP is short for Internet Message Access Protocol.
So migrating a PST to IMAP means uploading the mail from that local file to an online account, like a new Gmail, Office 365 or hosting mailbox. People do this when they switch providers, want their mail on every device or want the server to hold a safe copy instead of a single file. The reverse, IMAP to PST, downloads a server account into a local file you keep as a backup.
One quick note on files. When you add an IMAP account, Outlook keeps a local cache in an OST file, not a PST. So to make a portable PST from an IMAP account, you export it, which is the backup step further down.
Both directions are a job for classic Outlook, since the new Outlook has no Import/Export wizard. The steps below cover the upload first, then the backup.
Migrating PST to IMAP uploads the file, the reverse downloads a backup.
“The confusion I see most is people running Export to a file and expecting it to reach the server. It won’t, that just writes another local PST. To get a PST onto an IMAP server you add the account in classic Outlook, open the PST and drag the folders into the account, and Outlook syncs them up. Going the other way, Export to a file is exactly right, it pulls the account down into a PST you keep. On a large mailbox the upload is slow, so for many gigabytes or lots of PST files, a tool that pushes straight to the server without Outlook is the calmer path.” Shubham Dixit, Email Migration reviewer (draft, pending approval)
How do you migrate a PST to an IMAP server for free?
You migrate a PST to an IMAP server for free inside classic Outlook. You add the account, open the PST, then drag the mail across. Outlook uploads it to the server. No extra software is needed.
Here are the four steps.
- Add the IMAP account in classic Outlook, File then Add Account, so it shows in the folder list.
- Open the PST, File then Open & Export then Open Outlook Data File, and pick your .pst.
- Drag the folders or emails from the PST into the IMAP account’s folders in the folder pane.
- Wait while Outlook uploads the mail to the server. The folder structure and attachments carry over.
When I moved a 6 GB PST this way, the upload ran overnight, so plan for time on a large mailbox. If the account uses two-step verification, like Gmail or Yahoo, turn IMAP on in the account’s settings first, then create an app password or sign in with OAuth2.
There’s a tidier alternative to dragging. Instead of opening the PST, use File, Open & Export, Import/Export, Import from another program or file, then Outlook Data File, and pick your IMAP account as the destination. Outlook copies the PST into the account and keeps the folder structure, so you skip the manual drag.
If you add the IMAP account by hand, the common settings are the server (for example imap.gmail.com), port 993 with SSL/TLS, and your email as the username. Outlook fills these in for known providers.
Add the account and open the PST, then drag the folders in for Outlook to upload.
How do you back up an IMAP account to a PST?
You back up an IMAP account to a PST with Outlook’s Export to a file. This is the reverse of the upload, and it’s the answer people search for as convert IMAP to PST. It writes the whole account to a local .pst you keep.
Here are the four steps, and you can confirm them in Microsoft’s own guidance.
- Add the IMAP account in classic Outlook so it syncs down to your PC.
- Go to File, Open & Export, Import/Export, then Export to a file.
- Choose Outlook Data File (.pst), then select the IMAP account and the folders you want.
- Save the .pst on your computer. That file is your backup, and you can open it any time.
How do you migrate PST to IMAP in bulk without Outlook?
You migrate PST to IMAP in bulk without Outlook by using a converter. A converter reads the PST and pushes the mail straight to the IMAP server, so there’s no dragging and no Outlook to wait on.
The PCDOTS PST Converter opens one or many PST files and exports them to an IMAP account, using the server, port, email and password you enter. It keeps the folder structure and attachments, runs on Windows and works locally, so nothing sits on a third party server. The free trial moves the first 10 items per folder, so you can test the connection first. Follow these four steps.
- Install and run the PCDOTS PST Converter, then open the menu.
- Add your PST files or a whole folder.
- Open Export, choose IMAP, then enter the server, port, email and password.
- Start the export, and the tool uploads the mail to the IMAP account.
The tool route, PST files pushed straight to the IMAP server.
Here are the same four steps with the screens.
Step 1. Install and run the PCDOTS PST Converter.
Step 2. Add your PST files or a whole folder.
Step 3. Open Export and choose IMAP.
Step 4. Enter the server, email and password, then start.
Related reading, our guides to export Outlook emails to EML and convert a PST file to CSV. To read a .pst first, the free PST viewer opens one without Outlook.
The settings any IMAP connection needs, whether by hand or through a tool.
Which PST to IMAP method should you use?
Use Outlook’s drag method for a small PST, and a converter for large or many PST files. Both put the mail on your IMAP server.
| Method | Best for | Good to know |
|---|---|---|
| Outlook drag to IMAP | A small PST | Free, classic Outlook, slow if large |
| Export to a file | Backing IMAP up to PST | Free, the reverse direction |
| PST Converter | Large or many PST files | Windows, no Outlook needed |
Key takeaways
- Migrating PST to IMAP uploads a local file to a server account, and it’s a classic Outlook job.
- Add the IMAP account, open the PST, then drag the folders in for Outlook to upload.
- Export to a file goes the other way, backing an IMAP account up to a PST.
- For large or many PST files, a converter pushes to the server without Outlook.
Frequently asked questions
How do I move a PST file into an IMAP account for free?
Add the IMAP account in classic Outlook, open the PST with Open Outlook Data File, then drag the folders into the account. Outlook uploads them to the server.
Does Export to a file upload my PST to IMAP?
No. Export to a file only writes a local PST. To reach the server you must drag the mail into the IMAP account, or use a tool that pushes to IMAP.
How do I convert or export IMAP to PST?
Add the IMAP account in Outlook, then use File, Open and Export, Import/Export, Export to a file, Outlook Data File, then select the account to save a PST backup.
Can I do this in the new Outlook?
No. The new Outlook has no Import/Export wizard, so PST and IMAP moves need classic Outlook, or a converter that works on its own.
Why is the upload so slow?
Outlook uploads every message to the server, so a large PST can take hours. A direct converter is faster for big or multiple PST files.
Will my folders and attachments stay intact?
Yes. Dragging into an IMAP account and a good converter both keep the folder structure and attachments during the move.
Which way are you moving your mail?
Migrating PST to IMAP is simple once you picture it as an upload. Add the account in classic Outlook, open the PST, drag the folders in and let it sync. Going the other way, Export to a file writes the account back to a PST you keep. For a big archive or a stack of PST files, a converter skips Outlook and pushes straight to the server. So the only thing left to decide is this, are you uploading a PST to a server, or pulling a server account down into a PST?
