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Stellar Converter for OLM is Windows software that converts Outlook for Mac OLM archives to PST and other formats. Stellar says it preserves mailbox folders and data, but the available product information does not independently establish lossless results. Its desktop trial lets you preview converted items; saving them requires a paid license. Treat the preview as a check before purchase, then validate the saved file in the Outlook environment where you plan to use it.
What Stellar Converter for OLM does
OLM is Outlook for Mac’s archive format. Stellar’s Windows desktop application scans an OLM file and offers conversion to Outlook PST, as well as MSG and EML. Stellar lists emails, attachments, contacts, calendars, tasks, and notes as supported mailbox components, and says the software retains the original folder hierarchy and mail settings. These are vendor-described capabilities, not independently verified conversion results. See Stellar’s product features and specifications.
The output options depend on edition. Stellar lists PST, MSG, and EML for Standard; Technician adds PDF, HTML, RTF, and direct export to Microsoft 365. Check the current edition details on Stellar’s purchase page before choosing, since product features can change.
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According to Stellar, the desktop trial previews converted items, but a license is required to save converted data. A preview can help you inspect whether expected mailbox components and folders appear; it is not a saved PST and cannot confirm that the complete output will work in your destination Outlook setup.
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Stellar’s product page currently identifies version 6.0.0.0, released in January 2026. It lists Windows 11, 10, 8.1, and 8; a 64-bit Intel-compatible processor; 4 GB minimum memory (8 GB recommended); and 250 MB of free disk space. These requirements are time-sensitive. Confirm the current installer and edition requirements on the product page before installing.
How to evaluate a conversion safely
Use a copy of the OLM archive and keep the untouched original until you have checked the destination. Stellar’s published desktop workflow is to locate or browse to the OLM file, scan it, preview mailbox components, choose an output and destination, then save. Its screens show options to save mailboxes as separate PST files or as one PST. The precise controls can vary by version; Stellar’s workflow screenshots illustrate the vendor’s described process.
- Protect the source. Make a separate copy of the OLM archive and leave the original unchanged.
- Record what you are evaluating. Note the application version and edition so you can interpret the available output choices.
- Inspect representative content in preview. Check several folders and item types, including messages with attachments, contacts, and calendar items if they matter to you.
- Save to a new location. Choose the required output format and destination rather than overwriting existing archive files.
- Validate in the intended destination. Open or import the saved PST in the Outlook environment where it will be used. Compare important folders, date ranges, attachments, contacts, and calendar entries against the source.
- Keep the original until validation is complete. A successful-looking preview alone is not a reason to discard the OLM archive.
These checks are prudent archive-migration steps, not reported test results for Stellar. No independent, named, dated success-rate statistic or controlled conversion study is established by the available product material. Stellar uses broad precision and integrity language without providing a sample size or methodology there, so “without data loss” should not be treated as a proven guarantee.
Desktop app or online converter?
Stellar also offers an online OLM converter, which is a separate service rather than a mode of the desktop application. Stellar describes the online output as PST-only and states a free limit of one OLM file up to 100 MB. Its paid online option covers five files of up to 5 GB each. Stellar says uploaded and converted files are automatically deleted after 24 hours; this is the vendor’s retention statement, not an independent audit. Details are on the online converter page.
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| Option | Outputs and destination | Trial or stated limits | Processing and privacy consideration |
|---|---|---|---|
| Desktop Standard | PST, MSG, EML, according to Stellar | Trial previews; saving requires a license | Windows desktop software; verify current system requirements and edition details on Stellar’s product page. |
| Desktop Technician | Standard formats plus PDF, HTML, RTF, and direct Microsoft 365 export, according to Stellar | Trial previews; saving requires a license | Windows desktop software; confirm current edition features on Stellar’s purchase page. |
| Online converter | PST, according to Stellar | Free: one file up to 100 MB. Paid: five files up to 5 GB each, as stated on the service page | Requires uploading the archive. Stellar states uploaded and converted files are deleted after 24 hours; review current privacy terms before uploading sensitive mail on the service page. |
Choose based on your needed destination and formats, whether you want local desktop processing or are comfortable uploading the archive, and the file-count and size limits. Do not apply the online service’s limits or retention statement to the desktop application.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Is it a dependable choice for OLM-to-PST migration?
Stellar documents a workflow and advertises several export formats and mailbox components, which can make the product a candidate when you need to move Outlook for Mac archive data into a Windows-oriented Outlook workflow. However, the available evidence supports describing its features, not certifying a lossless conversion. Use the preview to inspect what the trial exposes, and rely on the converted PST only after checking it in its intended Outlook destination. Confirm current version, compatibility, and edition features directly with Stellar before purchase.
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