SCANPST: where it is, what it fixes, and when it fails

SCANPST.EXE, the Microsoft Outlook Inbox Repair Tool, is installed with classic Outlook. It checks a PST’s internal structures and rewrites the parts it finds damaged.

Where SCANPST is

It is in the Office program folder. For current Microsoft 365 and Office 2016–2024 installations:

• C:\Program Files\Microsoft Office\root\Office16\SCANPST.EXE (64-bit Office)
• C:\Program Files (x86)\Microsoft Office\root\Office16\SCANPST.EXE (32-bit Office)

Older versions use Office15 (2013) or Office14 (2010). If it is not there, search the Microsoft Office folder for SCANPST. It is not available for Outlook for Mac or the new Outlook.

How to run it safely

1. Close Outlook.
2. Copy the PST and run SCANPST on the copy. SCANPST rewrites the file in place; a copy keeps the original if something goes wrong.
3. Start SCANPST.EXE, Browse to the copy, click Start. The scan can take a long time for large files.
4. Read the summary. If it reports errors, keep Make backup of scanned file before repairing checked and click Repair.
5. Open the repaired copy in Outlook (File › Open & Export › Open Outlook Data File). Recovered items may appear in a Recovered Personal Folders or Lost and Found folder.

Run it again until it reports no errors; several passes are sometimes needed.

What SCANPST can and cannot fix

SCANPST fixes damaged internal indexes, folder tables, free-space maps and size counters, the most common kinds of damage after a crash. It is weaker when:

• large parts of the file are overwritten or missing,
• the file is near or over its size limit,
• the damage hits the file’s main index.

When it fails, it often stops with a generic error or loops without finishing. It also does not tell you which messages it dropped.

An alternative that never edits your file

Our Repair PST works differently: a free health check reads every part of the file and lists exactly what is damaged and how many messages can be recovered. Repair then copies every readable message into a new PST, checks each one against the original, and names anything it could not save in a report. Your original file is never changed, and it runs in your browser on Windows, Mac and Linux.

Frequently asked

Is SCANPST safe? It is Microsoft’s own tool, but it changes the file it repairs. Always use a copy.

SCANPST says “no errors” but Outlook still fails. The problem is likely not damage: see Outlook data file cannot be accessed for the other causes.