How to Repair a Corrupt Outlook Data File with ScanPST

Outlook crashes, freezes, or shows missing/empty folders — classic signs of a corrupt .pst data file.

Why: A PST can become damaged by an improper shutdown, a full disk, or a very large file. Microsoft ships a free Inbox Repair Tool, ScanPST.exe, that scans and repairs the file’s structure. Back up the PST first — it’s your only copy of that mail.

Fix 1: Find ScanPST.exe

Close Outlook completely, then open the folder for your version in File Explorer:

• Microsoft 365 / Outlook 2021 / 2019 / 2016: C:\Program Files (x86)\Microsoft Office\root\Office16
• 64-bit installs: try C:\Program Files\Microsoft Office\root\Office16
• Outlook 2013: C:\Program Files (x86)\Microsoft Office\Office15

If it isn’t there, search the C: drive for scanpst.exe. Double-click it to launch.

Fix 2: Locate your PST path

You’ll need the file’s full path inside ScanPST.

1. Reopen Outlook briefly → File → Account Settings → Account Settings → Data Files tab.
2. Note the full path of the .pst (click Open File Location to confirm).
3. Close Outlook again before scanning.

Fix 3: Scan and repair

1. In ScanPST, click Browse, select your .pst, and click Start.
2. Let it scan (large files take a while). If it reports errors, tick “Make backup of scanned file before repairing” and click Repair.
3. When it finishes, reopen Outlook and check your folders. Severe corruption may need several passes — run Repair again until it reports no errors.

Fix 4: For an OST, delete instead of repair

An .ost is just a cache of an Exchange/365 mailbox, so don’t bother repairing it — close Outlook, rename the .ost to .old (find its path in Data Files), and reopen Outlook; it rebuilds the cache from the server automatically.

FAQ

Will ScanPST delete my email? It repairs structure and can drop unrecoverable items, which is why you tick the backup option — it saves a .bak copy of the original before changing anything.

ScanPST says it can’t repair the file — now what? If repeated passes fail, the PST is too damaged for the built-in tool. Restore from your most recent backup, or recover what you can by creating a new PST and dragging readable folders into it.

Sources: Microsoft Support — Repair Outlook Data Files (.pst and .ost)