MailtoPst
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PST OLM

Convert PST to OLM
Online Tool

Convert PST files to OLM format online. Free tool, EU servers, GDPR compliant, auto-delete 24h. No software to install.

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🛡️ GDPR Compliant 🔒 TLS 1.3 Encryption 🇪🇺 Hosted in EU 🇫🇷 Built in France 🗑️ Auto-delete 24h

What is a PST file?

PST (Personal Storage Table) is the file format used by Microsoft Outlook. It stores email messages along with their metadata, attachments, and folder structure.

PST files are commonly encountered when:
- Migrating between email platforms — switching from Microsoft Outlook to another system
- Email archiving — long-term storage of email communications
- Legal and compliance — eDiscovery and regulatory requirements
- Backup and recovery — protecting email data from loss

While PST is widely used in its native ecosystem, working with these files outside of Microsoft Outlook can be challenging without proper conversion tools.

What is a OLM file?

OLM (Outlook for Mac Archive) is the format used by Outlook for Mac. It provides a structured way to store and organize email messages with full support for attachments, metadata, and folder hierarchies.

OLM is the preferred format for:
- Outlook for Mac — native file format for import and export
- Cross-platform compatibility — supported on macOS only
- Email archiving — reliable long-term storage
- Data migration — widely accepted by email migration tools

By converting to OLM, your emails become accessible in Outlook for Mac and compatible email applications.

Why convert PST to OLM?

Converting PST to OLM is essential in several scenarios:

1. Migrating to Outlook for Mac
If you're moving to Outlook for Mac, converting PST to OLM allows you to import your entire email archive with folder structure and metadata preserved.

2. Cross-platform access
PST files require Microsoft Outlook to open natively. Converting to OLM makes your emails accessible on macOS only.

3. Email archiving and compliance
Organizations often need to convert email archives between formats for legal discovery, compliance requirements, or long-term storage strategies.

4. Opening emails without Microsoft Outlook
If you receive a PST file but don't have Microsoft Outlook, converting to OLM lets you access the emails in Outlook for Mac or any compatible client.

PST vs OLM — Key Differences

Feature PST OLM
Ecosystem Microsoft Outlook Microsoft Outlook for Mac
File structure Binary database (B-tree) ZIP-based XML archive
Openness Proprietary Microsoft format Proprietary Microsoft format
Platform Windows (Outlook required) macOS only
Data types Email + calendar + contacts + tasks Email + calendar + contacts
Free readers Very limited None (Outlook for Mac only)

3 methods to convert PST to OLM

Method 1: Manual conversion via email client

Import the PST file into a compatible email client, then export in OLM format. This requires having both source and target applications installed.

Pros

  • ✓ Free if you already have the software
  • ✓ Full control over the process

Cons

  • ✗ Requires specific software installed
  • ✗ Multi-step manual process
  • ✗ Time-consuming for large files
  • ✗ Risk of data loss during manual steps

Method 2: Desktop conversion software

Several desktop converters can handle the PST to OLM conversion locally. These paid tools typically cost between $29 and $99 per license.

Pros

  • ✓ Direct conversion
  • ✓ Works offline

Cons

  • ✗ Paid ($29-$99)
  • ✗ Windows only
  • ✗ Installation required
  • ✗ Limited file size support
Recommended

Method 3: MailtoPst (online, free trial)

Upload your PST file to MailtoPst, select OLM as the output, and download. Works from any browser, no software needed.

Pros

  • ✓ First conversion free
  • ✓ No Microsoft Outlook needed
  • ✓ Works on Mac, Linux, Windows
  • ✓ Preserves folder structure
  • ✓ GDPR compliant, EU servers

Cons

  • ✗ Requires internet connection
  • ✗ Paid after first conversion
Try MailtoPst →

Step by step

How to convert PST to OLM with MailtoPst

01

Upload your PST file

Drag & drop or click to upload your .pst file. Files up to 51 GB supported with resumable upload.

02

Choose OLM as output

Select OLM from the format dropdown. MailtoPst auto-detects the best conversion settings.

03

Download your OLM file

Conversion takes seconds. Download your .olm file or receive it by email.

Convert your PST to OLM now →

100 MB free credit. No credit card required.

FAQ

Frequently Asked Questions

Can I convert PST to OLM without Microsoft Outlook?

Yes. MailtoPst reads PST files server-side — you don't need Microsoft Outlook installed. Just upload the file from any browser on any operating system.

Will my folder structure be preserved?

Yes. MailtoPst preserves the original folder hierarchy from your PST file when converting to OLM.

Is PST to OLM conversion free?

Your first conversion is free with no credit card required. Credit packs start from €4.99.

What about attachments and metadata?

MailtoPst preserves all attachments, email headers, timestamps, read/unread status, and other metadata during the conversion.

How large can my PST file be?

MailtoPst supports files up to 50 GB with resumable upload technology. If your connection drops, you can resume where you left off.

Related conversions

EML → PST MBOX → PST MSG → PST OLM → PST PST → MBOX
See all 30 conversion paths →

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