The software says the OST file is inaccessible or locked. What should I do?

Close Outlook completely. Make sure the Microsoft Outlook process is not running in Task Manager. Then reload the file. If it is still locked, copy the OST to another folder. Convert the copy.

The conversion is slow. How can I speed it up?

Close other programs that use a lot of memory. Save the output to a drive instead of a network or USB drive. Use folder or date filters to convert only what you need. Split very large outputs into multiple PSTs.

The converted PST won't open in Outlook. What's wrong?

Check that the PST is not marked as read-that the Outlook version supports the PST format (Unicode PSTs aren't supported in Outlook 2002 and earlier) and that the file isn't too big. If the problem continues run the Inbox Repair Tool (scanpst.exe) on the PST.

Some items are missing after conversion. Why?

Items that were never copied to the OST (for example mail that is on the server) can't be converted. Check the Deleted Items & Recoverable Items folders. Run the scan again with deleted-item recovery turned on.

OST to PST Converter to Convert Offline OST Files to PST

Q: How can I contact support?

Get in touch with the support team via Chat Support. Technical support is available 24*7.

Benefits of

The Best OST to PST Converter

Easily convert OST to PST with full data integrity of emails, calendars, contacts, & attachments.
Designed to convert single or multiple OST files to PST & other supported formats.
Protect the original folder layout, metadata, and email properties with complete
accuracy.
Seamlessly converts OST files into PST, MBOX, EML, MSG, PNG, CSV, MD, JSON, and
Mozilla Thunderbird.
Enables export to document formats such as PDF & DOCX.
Offers an option to save contacts as a VCF and calendar data into ICS format.
Supports OST migration to Microsoft 365, Google Workspace, IMAP Server,
Outlook.com, and GoDaddy.
Allows users to examine or preview all mailbox contents before starting the conversion process.
Convert large OST files seamlessly without any size limitations using the OST to PST
Converter.
Identifies and deletes duplicate emails based on To, From, Subject, Bcc, and Body.
Optimize storage space by backing up emails without including attachments.
Operates on all Windows OS and Microsoft Outlook versions.

Exclusive Features

OST to PST Converter Tool

Secure

End-to-end Secure OST to PST Conversion

The Cigati OST to PST Converter Tool guarantees secure and complete OST to PST conversion, while retaining all essential data such as emails, contacts, calendars, and attachments. Throughout the conversion, it ensures a safe conversion without losing any valuable information.

Bulk Conversion

Efficient Bulk or Single OST File Conversion

The Cigati software can convert one OST file or an entire enterprise mailbox library simultaneously into PST and other formats, simplifying bulk data management and migration. Users can perform migration in full throttle with no downtime across large deployments.

Multiple files

Easily Save OST Files Locally in Multiple Formats

With the help of the Outlook OST to PST Converter, users can also export OST data directly to PST, MBOX, EML, DOCX, PNG, D, JSON, MSG, ICS, VCF, and Mozilla Thunderbird. It also migrates directly into email clients such as Office 365, Google Workspace, Gmail, Outlook.com, GoDaddy, & IMAP Supported Servers.Gmail, Outlook.com, Office 365, Yahoo Mail, AOL Mail, Zoho Mail, Roundcube, cPanel, Zimbra, Proton Mail, iCloud, GMX Mail, Mail.com, FastMail, Yandex Mail, Mozilla Thunderbird, Apple Mail, em Client, Mailbird, Mail Spring, Spark Mail, BlueMail, Canary Mail, SeaMonkey Mail, Pegasus Mail, & Any IMAP Server

skip

Skip Existing Exports & Detect Duplicates

The Skip Existing Exports option prevents already exported mailbox items from being processed again. This software also detects duplicate emails by comparing key fields, including To, From, CC, Subject, & Body. This helps avoid repeated data, reduces unnecessary processing, & keeps the exported mailbox clean and organized.

Contact

Convert Contacts and Calendars from OST Files

With the convert OST to PST Tool, users can convert OST contacts to VCF and calendar events to ICS format, allowing smooth sharing and universal accessibility across different email clients, mobile devices, and productivity applications.

Without Attachments

Perform Email Migration without Attachments

The OST to PST Converter helps users to export attachments separately, merge attachments, or exclude attachments, giving granular control over file size, compliance, & data governance. This makes sure smooth handling of bulk data without affecting system performance.

Date Range

Date-Range Filtering with Custom Folder Naming

With the Cigati OST to PST Software, users are provided with the ability to filter emails by date by defining precise start and end dates to scope conversions and assign personalized folder names to output PST files, ensuring consistent metadata and easier archival.

hierarchy

Smart File Naming & Folder Hierarchy

The file naming policy keeps migrated data organized by following the existing tree hierarchy. Files are named consistently and mapped to their corresponding default folders, preserving the original structure. This approach makes it easier to identify, locate, & manage mailbox data after migration while maintaining a clear relationship between source folders and their destination locations.

safe-and-secure

Secure Mapping Option

Microsoft 365 & Google Workspace Mapping helps users match source mailbox folders with their corresponding destination folders during migration. It keeps the folder structure organized & makes sure emails are placed in the correct locations. Users can map folders according to their requirements, making large-scale OST migrations more structured, accurate, and easier to manage.

Comaptible

Universal Platform Deployment

The Cigati software is fully compatible with Windows and macOS environments. The solution can be implemented across mixed operating system environments. The enterprise IT teams can standardize on a single backup solution regardless of endpoint or server operating system.

Technical Specification

Software Prerequisites & Recommendations

Software Name:	Cigati OST to PST Converter
Version Support:	Windows 11 & below versions
Software Size:	246 MB
Version:	26.06
Last Updated:	June 2026
Download Link:	Download

Processor:

Hard Disk:

Memory:

Operating System:

Trial limitation:

The Offline OST to PST Converter is trial software. It is for evaluation purposes and can back up only 50 items per folder. For unlimited conversion, consider purchasing the full version.

Download Guide:

Software Guide

Installation / Uninstallation

Eula

Software Features	Free Version	Full Version
Easily Convert OST to PST	50 Items per folder
Export contacts and calendars to VCF and ICS formats	50 Items per folder
Import single or multiple OST files
Preview OST emails along with attachments
Filter out duplicate emails before conversion
Mapping Mailbox
24*7 Tech Support & 100% Secure
Download and Purchase	Download	Purchase

FAQ

Frequently Asked Questions

It reads Outlook Offline Storage Table files. Converts them into PST files that Outlook can import directly. Emails, contacts, calendars, tasks, notes & journal entries are kept along with their folder structure.

Yes. Both formats are. The output PST can be created in either format.

Emails with attachments, contacts, calendar entries, tasks, notes, journal items and distribution lists. The original folder hierarchy. Unread status and item properties are kept.

Yes it can recover items from the Deleted Items folder. If the data is still in the file even permanently deleted items. Recovered items can be. Excluded during export.

No. The source file is opened in read- mode and is never changed.

Yes. After scanning you can look at the mailbox tree. Choose specific folders or items or use filters like date range, sender or subject.

Yes. You can set a size such as 5 GB, 10 GB or 50 GB & the tool creates multiple PST files automatically. This helps avoid the 50 GB PST limit and stops performance problems in Outlook.

Yes. All recoverable items can be seen in a three-pane view before you export.

If your edition supports it you can move OST data directly to an Exchange mailbox or Microsoft 365 account by giving your login details skipping the PST file.

Get in touch with the support team via Chat Support. Technical support is available 24*7.

Client Review

A Glimpse into Client Experiences

Thousands of satisfied customers have chosen our software and praised its reliability and performance. They have shared positive stories about how the Cigati OST to PST Converter has helped them manage their data efficiently.

"We migrated 3,200 mailboxes across six offices with no downtime, zero data loss. Our IT Administrators ran the entire operation from a single machine. Cigati performed exactly as promised, migration in full throttle."

Marcus R | France

"As an IT Consultant, I've tried every tool on the market. Cigati OST to PST Converter is the only one I trust for client-facing migrations. It maintained the folder hierarchy throughout the conversion. "

Sophia | USA

"Our startup needed to move fast during a Microsoft 365 rollout. The convert OST to PST Tool had us fully migrated over a weekend. Business users didn't even notice anything changed, that's exactly what we needed."

Cigati OST to PST Converter

The Best OST to PST Converter

Microsoft OST to PST Converter: Enterprise Migration Demands