Outlook’s PST file is fragile. A sudden shutdown mid-sync, an oversized mailbox pushing past Outlook’s limit, or a failing hard drive could corrupt your PST file. As a result, you could lose your emails, contracts, calendar, and other data. You could also see errors like “File in use” or “Not recognized as a personal folder file,” and so on.

Thankfully, several tools can help, including Outlook’s built-in Inbox Repair Tool (scanpst.exe) and third-party options like Stellar Online PST Repair or Stellar Repair for Outlook. The Stellar tools promise to fix your corrupted PST file. But which one’s better? Let’s find this out in our review.

What Are Stellar Online PST Repair & Stellar Repair for Outlook tools?

Stellar PST Repair for Outlook is a Windows program built to handle tough cases such as badly damaged files, huge PST files, or files Outlook can’t even open.

Stellar Online PST Repair does the same basic job, but through your web browser. You don’t have to install anything. Instead, upload your damaged PST file to the website, let it repair it, then review the recovered data before saving it.

Key features of Stellar Online PST Repair & Stellar Repair for Outlook

1] Repairing corrupt and oversized PST files

On the other hand, scanpst.exe is built only for small, surface-level problems. However, if you push its limits by trying to repair a badly damaged or oversized file, the tool tends to fail or stall. As a result, you may never be able to repair your PST file.

On the other hand, Stellar Repair for Outlook is a much better option because it can handle severely corrupted files and oversized PSTs with no size cap. Even if Outlook refuses to open a file, Stellar can recover it.

2] What you actually get back

Both the tools offered by Stellar bring back your essential data, such as emails, contacts, calendar entries, and more. Although the desktop tool is a little better, as it can recover notes and journal entries, plus it flags any recovered deleted items separately so you can decide what to do with them instead of them quietly mixing back into your inbox.

On the other hand, scanpst.exe doesn’t try to recover deleted items at all. It only tries to recover what’s available in the file.

3] Preview files

Using both Stellar tools, you can preview your recoverable files and folders. This lets you decide whether you want to recover anything. But scanpst.exe has no preview feature. As a result, it recovers everything, and you can see your files after it finishes.

4] Export and output options

With Stellar Repair for Outlook, it saves your recovered data as a PST file. If you’re using the Technician Edition, you can send it straight into a Microsoft 365 or Live Exchange Server mailbox. This is useful if you’re migrating a mailbox rather than just reopening it. However, scanpst.exe only repairs the PST file and offers no other options.

Feature comparison

Feature	Stellar Online PST Repair	Stellar Repair for Outlook (Desktop)
Installation	No installation; runs in browser	Requires software installation
File Size Limit	Up to 5 GB (free tier often capped at 500 MB)	No size limit; handles very large PST files
Speed & Convenience	Quick, automated cloud repair; upload & download	Local processing, avoids upload delays
Data Recovery Scope	Maintains mailbox structure; preview in browser	Full recovery: emails, contacts, calendars, attachments, notes
Export Options	Download repaired PST; limited formats	Multiple formats (PST, EML, MSG, RTF, HTML, PDF, MBOX) + direct migration to Office 365/Exchange
Best Use Case	Fast fix for small/medium PST corruption	Heavy-duty repair of large, severely corrupted, or sensitive PST files

Note: Besides the desktop app, you also have an online tool that does the same job. This means the online tool can restore your emails, contacts, calendars, and attachments. Compared to scanpst.exe, it repairs the file with minimal configuration. It also lets you preview your files before you save anything.

Stellar Online vs Desktop PST Repair: What’s the real difference?

Since both tools are better than scanpst.exe and let you recover your PST file with ease, the next question is: desktop vs online, which one is actually good? Both tools work pretty much the same way. But the desktop option is the stronger choice.

First, the desktop tool has no size limit and is built to recover severely corrupted files. The online tool works better for smaller files and lighter damage. Also, for larger files, the desktop tool is much faster because you don’t need to upload your files. But online is a better choice if you want to get started fast. Moreover, with the desktop tool, you can send your data to Microsoft 365 or Exchange once the PST file is recovered.

Overall, if you have a large, severely damaged mailbox and want full control over where your data ends up, the desktop tool is a better choice.

In the end, both tools use the same repair technology. But they’re built for different use cases. If your PST file is large or seriously damaged, then Stellar Repair for Outlook is the stronger choice. If you just need your file working again fast, without installing anything, Stellar Online PST Repair can be a good choice too.