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Stellar offers two ways to attempt a PST repair: an online service that requires uploading the file, and a Windows desktop application that its product page describes as processing files locally. Before paying for either, try Microsoft’s built-in Inbox Repair Tool, SCANPST.EXE, which can diagnose errors in Outlook data files and offer to fix errors it finds. None of these options guarantees recovery from every damaged file.
Start with Microsoft’s Inbox Repair Tool
Microsoft documents SCANPST.EXE as a utility for diagnosing errors in Outlook data files. If it finds errors, the utility gives you the opportunity to allow it to fix them. Microsoft does not present this as a guarantee that every corruption problem can be repaired. See Microsoft’s instructions for repairing Outlook data files.
Keep an untouched copy of the PST before attempting repairs. Work on a duplicate where possible, and avoid overwriting the only copy of a file that contains data you need. If SCANPST.EXE does not resolve the problem, or you need to inspect recoverable items before deciding what to save, a third-party tool may be worth considering.
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1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsHow Stellar’s online and desktop options differ
The online service runs in a browser and requires you to upload the PST. The desktop product is installed on Windows; Stellar describes its repair processing as local. The differences in workflow, limits, and listed features are documented vendor claims, not independent evidence that either option will succeed on a particular damaged file.
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| Consideration | Online PST repair | Desktop Professional |
|---|---|---|
| How it works | Browser-based; upload the PST to the service. Stellar says files are processed over a secure connection without a human touchpoint. | Installed Windows application; Stellar describes processing as local. |
| File limits | Stellar displayed a free plan for one file up to 500 MB and a $29.99 per-file option for files up to 5 GB, as accessed on October 7, 2026. | The product page describes unlimited file size and file count for Professional; confirm current terms on the live page. |
| Availability of repaired files | Stellar says free-plan files remain available for 24 hours and paid-plan files for 48 hours, then are automatically and permanently deleted from its servers. | Local processing is described on the product page. The page says a licensed Microsoft Outlook installation is required to complete repair and save recovered data to a new PST; verify current instructions before purchase. |
| Listed compatibility | Stellar lists PST files from Outlook 2003 through 2024, including ANSI and Unicode formats, and modern versions of Chrome, Firefox, Edge, and Safari. | Stellar lists Outlook 2016, 2019, 2021, and 2024, and Windows 11, 10, 8.1, and 8 (64-bit). Its stated minimum memory is 8 GB, with 16 GB recommended. |
| Displayed price | One file up to 500 MB free; $29.99 per file up to 5 GB for the paid option, as displayed October 7, 2026. | Professional displayed at $79, as accessed October 7, 2026. |
| Preview and saving | The online page describes downloading the repaired file. Its FAQ addresses where the file is saved after download. | The trial is described as allowing preview of recoverable items. The product page lists saving recovered data to a new PST, subject to the Outlook requirement above. |
Check the current online service terms and desktop product details before relying on prices, availability windows, compatibility, or system requirements. These are volatile vendor-displayed terms, not permanent prices.
Choose based on file size, privacy, and what you need to save
The online service may suit a smaller file and browser-based workflow
The online plan limits and retention windows make file size and timing practical considerations. The free option displayed by Stellar covers one file up to 500 MB; the paid option displayed covers a file up to 5 GB. The service page says repaired files are available for 24 hours on the free plan and 48 hours on the paid plan. Plan terms may change, so verify them before uploading or paying.
Uploading means sending the PST to Stellar’s service. Stellar says uploads and repaired files are automatically and permanently deleted within the applicable 24- or 48-hour period, and describes processing as secure and without a human touchpoint. Those are the company’s statements, not an independent privacy certification. If your mailbox contains sensitive or regulated information, decide whether uploading it is acceptable under your organization’s rules before using the service.
The desktop product may suit local processing or larger files
Stellar describes the desktop application as repairing PST files locally and lists no file-size limit for Professional. That may be relevant if a file exceeds the online service’s displayed limit or you prefer not to upload it. Local processing does not by itself establish how well a damaged file will be repaired; it describes the stated workflow, not a recovery result.
The desktop page lists Windows 11, 10, 8.1, and 8 (64-bit), an Intel-compatible x64 or Snapdragon processor, 8 GB minimum memory (16 GB recommended), and 250 MB for installation files. It lists version 14.0.0.1 with a June 2026 release date. Requirements and version information can change; check the live product page against your computer before installing. The page also says a licensed Outlook installation is needed to complete repair and save recovered data to a new PST.
Preview is different from saving recovered data
The desktop trial is described as letting you preview recoverable mailbox items, including email, attachments, contacts, and calendar data. Previewing can help you assess whether items appear recoverable, but it is not the same as saving a repaired PST. Confirm what the trial permits and what a license unlocks on the current product and purchase pages before deciding.
Stellar’s online page describes a repaired file being downloaded after processing. If your need is to inspect items, save them to a new PST, or use a different export route, confirm the exact available output and requirements for the option you choose rather than assuming the two products behave identically.
A cautious repair workflow
- Preserve the original. Make a separate copy of the PST and keep the original unchanged. Do not test repair tools on the only copy.
- Try Microsoft’s utility first. Follow Microsoft’s current SCANPST.EXE instructions to diagnose the Outlook data file and allow repairs if offered.
- Match the next option to your constraints. Check the PST’s size against the online limits, or confirm that your Windows system meets the desktop requirements. Decide whether uploading the file is acceptable.
- Review current terms before committing. Check the live service page for price, maximum file size, retention window, and supported browser; check the desktop page for current price, system requirements, Outlook compatibility, and license requirements.
- Inspect and save deliberately. If the tool presents recoverable items, review them before relying on the result. Save recovered data to a new file where supported, then verify that the new file opens and contains the items you need before retiring the original.
What the listed features do—and do not—tell you
The vendor pages establish differences in stated workflow, compatibility, file limits, pricing, and preview or save features. They do not establish a recovery rate, prove that a particular PST can be repaired, or show which option will perform better on your file. The condition of the file and the data you need matter; preserve the original and verify any recovered output before treating the repair as successful.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
