Every Outlook user is aware of the importance of Offline Storage Table (.ost) files. These files store a synchronized copy of mailbox items like crucial email messages, business-sensitive contacts, event list, etc. It (.ost) is also referred as an offline folder. This is so because it allows access to mailbox data even during server downtime or network issues. Some factors also make Outlook data file (.ost) orphaned or inaccessible.
Let’s decode the main culprit behind this issue. In majority of cases, this issue is caused by OST file corruption. It happens when the file size exceeds its limit. Sudden Outlook closure can also lead to this situation. What to do next? How to access mailbox in such a situation? The solution in this case is OST to PST conversion.
Checkout our guide titled “OST to PST Converter Software: 5 Best to Use in 2025” to explore some of the best tools available in the market. This guide will tell you about the USPs of different converter tools. Evaluate their features and choose the best alternate for your requirements.
5 Best OST to PST Converter Software
Checkout the below guide to unearth popular tools for OST to PST conversion:
- Stellar Converter for OST: It is one of the most popular ost to pst conversion tool. This software is powered with a friendly interface. It is reliable, quick as well as trustworthy. This software is smart enough to convert even orphaned, or inaccessible data files. Its capability to efficiently convert large OST files is really commendable.
Features:
- It supports all Outlook versions (2021, 2019, and earlier)
- Can convert inaccessible .ost file to PST
- Can fix and convert an encrypted OST
- Ability to convert an orphaned .ost to .pst file format
- Capability to convert Outlook data file (.ost) of any size
- With advanced filter option for targeted conversion of mailbox folders
- Capability to recover deleted mailbox items
- Batch conversion of multiple OST files functionality (Technician version)
- Can facilitate OST file export to Office 365 as well as live Exchange Server directly (Technician version)
Pros:
- Ensures 100% data integrity
- Offers quick OST to PST conversion
- User friendly interface
- Functionality to export converted file in multiple formats
- 24/5 support for technical assistance
- Demo version available to preview converted items
Cons:
- The user can preview the entire mailbox content after conversion at no cost. It may be noted that the user can save only 20 items from each mail folder in the free version.
2: SysTools OST to PST Converter: It is another popular converter software. This tool is compatible with all Outlook versions.
Features:
- Can convert inaccessible .ost files
- Can convert orphaned OST to PST
- Facilitates data file export in different formats (EML, PDF, HTML, etc.)
- Can convert a large OST files
- Supports batch conversion
- It allows users to exports Contacts into vCard
- The user can also export Calendars in ICS Format
Pros:
- Converts with accuracy
- Maintains data integrity
- User-friendly interface
- Offers professional support
- Allows selective content export
Cons:
- May create compatibility issues in the absence of .NET framework 4.5
- No option to compact PST file
- Advik OST to PST Converter: It is a popular software. Some popular features of this tool are listed below:
Features:
- Compatible with all Outlook versions
- Converts all OST mailbox items
- Supports batch conversion of OST to PST format
- Can convert large OST file
- Maintains Mailbox Folder Hierarchy and Email Attributes
Pros:
- Easy to navigate interface
- Capable of exporting to different file formats
- Offers 24/7 customer support
- Advanced Email Filter Option
Cons:
- Compact PST option is not available
4: Kernel for OST to PST Converter: Many business and individual Outlook users also prefer this software. It is loaded with advanced features such as:
Features:
- Can convert orphaned OST to PST
- Capability to migrate OST data to Office 365 as well as to the Exchange Server
- Can transfer OST content to any web-based email client (Gmail, etc.)
- Allows multiple format export (PST, MSG, etc.)
Pros:s
- Converts OST to PST with accuracy
- Retains original folder structure
- Provides advanced filters options
Cons:
- The free version offers limited options
- The dominant features are offered only with the paid version
- No option to compact or split PST
5: Shoviv OST to PST Converter: It is another software for OST to PST conversion. This tool is loaded with advance features. It can retrieve all crucial data like sensitive email messages, contacts, etc. in an efficient manner.
Features:
- Can convert inaccessible OST to PST
- Ability to convert orphaned .ost to .pst
- Efficiently recovers permanently deleted OST files
- Ability to convert single as well as multiple OST files
- Can convert large size OST
- Previews mail items extracted from OST file
- No OST file size limit for conversion
- Previews OST items before saving to PST
Pros:
- Can convert large Outlook data file
- A user can export in multiple file formats (HTML, MSG, etc.)
- Maintains folder hierarchy and metadata
Cons:
- Does not distinguish the deleted items
Conclusion:
OST file corruption can lead to multiple issues. It can be the main reason for orphaned or inaccessible data file (.ost). In the above guide titled “OST to PST Converter Software: 5 Best to Use in 2025,” we shed light on the features of some best tools available for OST to PST conversion. These tools are smart enough to deal with the OST file corruption. After critically evaluating different converter tools, the users can vouch for Stellar Converter for OST. This software is quick and reliable. It has a friendly GUI. This software is available in 3 versions-Corporate, Technician, and Toolkit. Try now!