What ScanPST does
The Inbox Repair Tool, whose program name is SCANPST.EXE, checks a PST’s internal tables and folders for inconsistencies and attempts to repair them. It is installed with supported classic Outlook desktop installations; it is not a general download from an unrelated software site.
Microsoft describes the tool as a way to diagnose and repair errors in Outlook data files. It can remove unreadable or corrupt entries while rebuilding structures, so preserve the original even when the tool offers to create its own .bak backup.
How to run the Inbox Repair Tool
- Close Outlook.Also close any process that may be using the PST.
- Find ScanPST for your Outlook installation.Its location varies by Outlook edition, installation type, and 32- or 64-bit architecture. Use Microsoft’s current location table rather than guessing a path.
- Open
SCANPST.EXE.Select Browse and choose the protected working copy—not your only copy. - Select Start.Allow the scan to finish. If errors are found, keep “Make backup of scanned file before repairing” selected and choose Repair.
- Open the result in Outlook.Inspect the folders, messages, dates, and attachments that matter to you. Check any Lost and Found folder created by the repair.
Follow Microsoft’s maintained guide for the exact ScanPST locations and supported procedure. Paths can change between Office releases, so this page does not freeze a version-specific path.
Interpret the result before doing anything else
Outlook opens the repaired copy
Review the mailbox. If the content you need is present and Outlook behaves normally, you probably do not need another repair tool.
ScanPST reports more errors
Microsoft says the tool may need multiple passes to fully repair a file. Keep the original untouched and follow Microsoft’s guidance for running multiple ScanPST passes.
ScanPST finds no problem
The cause may be the path, file access, Outlook mode, or profile rather than PST structure. Use the cannot-open troubleshooting steps.
ScanPST fails or Outlook still refuses the file
After simple access causes are excluded, the PST may have damage outside what ScanPST could resolve. Preserve its output separately from the source.
When a structural diagnosis is useful
Consider another diagnosis only when ScanPST cannot recognize the working copy, cannot complete successfully, continues to report unresolved errors after the supported process, or Outlook still rejects the repaired result. The broader corrupt-PST repair guide explains what repair can and cannot recover.
CorrectPST can check supported Unicode Outlook PST files up to 7.5 GiB for a narrow class of structural damage. Free diagnosis can say whether the file is recognized and whether CorrectPST can offer its supported repair path. It does not guarantee recovery and it does not support OST, ANSI, password-protected, deleted, or oversized files.
ScanPST questions
Where can I download ScanPST?
ScanPST is installed with supported classic Outlook desktop versions. Use Microsoft’s instructions to locate your installed copy. Avoid websites offering an unrelated executable under the ScanPST name.
Can ScanPST inspect an OST file?
Microsoft’s current repair guidance covers both PST and OST data files, though an OST is normally a replaceable offline cache. CorrectPST is PST-only and does not repair or convert OST files.
Why does ScanPST need more than one pass?
A pass can expose inconsistencies that were hidden by earlier damage. Microsoft documents automatic rescans and multiple-pass behavior; keep working from protected copies and review the final mailbox, not just the scan message.