What is included in Stellar Toolkit for Outlook?

Repair corrupt PST – Fixes large, severely damaged Outlook data files
Convert inaccessible OST – Rebuilds orphaned OST mailboxes into PST
Split & compact – Reduces oversized PSTs to limit corruption
Merge and undelete – Consolidates PSTs and restores deleted mail
Core Capacity – Seven tools, no file-size limit on repairs
Important – Windows-only desktop tool, no Mac edition

What are the main benefits of Stellar Toolkit for Outlook?

Stellar Toolkit for Outlook is a Windows 7-in-1 utility suite that repairs, converts, and reorganizes Outlook PST and OST files from a single console. It targets the recurring problems Outlook administrators face, such as corrupt mailboxes, oversized PSTs, orphaned OST files, and lost passwords, without a separate program for each task.

One console – Launch all seven tools from one dashboard
No size cap – Repairs and converts PST/OST of any size
Office 365 export – Sends repaired data straight to Microsoft 365
Batch processing – Repairs or converts multiple files per run
Selective recovery – Filters mail by date or sender address
Resumable scans – Saves scan data to finish later elsewhere

Data loss is expensive: How backups help you avoid outages
For more background on backup planning, read our guide:

What does Stellar Toolkit for Outlook do?

It bundles seven separate Outlook utilities into one interface: Repair for Outlook, Converter for OST, Splitter, Compactor, Merge Mailbox, Undelete Email, and Password Recovery. The repair and conversion tools recover full mailbox data, including deleted items, and save the output as PST, MSG, EML, RTF, HTML, PDF, DBX, or MBOX. This matters when Outlook's built-in Inbox Repair Tool (scanpst.exe) stalls on large or badly corrupted files, since Stellar processes a PST of any size and keeps the original folder hierarchy intact. The single dashboard means an administrator does not switch between vendors to repair, then convert, then reorganize a mailbox.

What is the difference between Stellar Repair for Outlook Technician and the Toolkit?

The Technician edition only repairs corrupt PST files and can split or compact the file it has just repaired; the Toolkit adds standalone tools that work without first repairing a file. The Toolkit includes OST-to-PST conversion, PST merging, deleted-email recovery, and PST password recovery, none of which ship in the Technician build. Choose the Technician edition if your work is purely PST repair, and the Toolkit if you also handle orphaned OST files, scattered PSTs that need consolidating, or locked PST files. The table below maps the verified feature split.

Does Stellar Toolkit for Outlook run on Mac or Windows Server?

No, it is a 64-bit Windows desktop application supported on Windows 11, 10, 8.1, and 8, with no Mac edition and no Windows Server listed in the official specifications. In practice you install it on an administrator's or technician's workstation and point it at the PST or OST files you need to fix. It does not run on the mail server itself; instead it connects outward to Office 365 or Live Exchange when you choose those as a save destination. Mac-based Outlook teams should treat this as a hard stop, since OLM files and macOS Outlook profiles are outside its scope.

Which Outlook versions and file formats does it support?

It supports Microsoft Outlook 2021, 2019, 2016, 2013, and earlier versions, and the OST converter handles both encrypted and IMAP OST files. Repaired or converted mailboxes can be saved as PST, MSG, EML, RTF, HTML, PDF, DBX, or MBOX, which is useful when you need EML or MBOX output for a different mail client rather than another PST. The merge tool reads identity folders from around twenty email clients, including Outlook.com, Office 365, Gmail, Lotus Notes, and Apple Mail, and writes them into a single PST. This format range is what lets one technician migrate mixed mailboxes instead of buying a separate converter per format.

How does it handle very large or oversized PST files?

There is no file-size limit on repair or conversion, so a multi-gigabyte PST that crashes Outlook can still be scanned and rebuilt. The Splitter breaks a PST into parts in the 1–50 GB range by Date, Size, or Email ID, while the Compactor shrinks a file by moving attachments into a ZIP and clearing the Deleted Items and Junk folders. The Merge tool consolidates up to ten mailboxes at a time into one PST while keeping the source structure. For long scans, the Save and Load Scan option writes results to a DAT file so you can pause on one machine and finish the repair on another.

What should I check before choosing the Toolkit?

Confirm you actually need more than repair, because if your only task is fixing a corrupt PST, the cheaper Repair for Outlook Technician edition already covers that plus split and compact of the repaired file. The Toolkit earns its place when you also need standalone OST-to-PST conversion, PST merging, deleted-email recovery, or PST password recovery in one license. Check that all target machines run 64-bit Windows, since there is no Mac build. Also note the free demo scans and previews recoverable items but does not save full output until you move to the paid version.

Frequently asked questions about Stellar Toolkit for Outlook

Can it open an OST file when no Exchange account or Outlook profile is available?

Yes. The Converter for OST tool opens an orphaned OST of any size without a live Exchange connection and extracts the mailbox into a PST. This is the practical fix when an Exchange mailbox has been deleted or purged and the OST is the only remaining copy of the data.

Does the free demo let me save recovered data?

The free demo runs with limited functionality: it scans and previews recoverable mail items so you can confirm a file is repairable before buying, but full saving is reserved for the activated version. The OST converter's free version exports a small sample of 20 emails, which is enough to validate the result on a specific file.