When Outlook starts throwing errors about a corrupt PST file, the go-to fix is Microsoft’s built-in Inbox Repair Tool: scanpst.exe. The problem is that Microsoft does not put it in an obvious location, and the path changes with every version of Office. This guide covers exactly where to find it and how to use it.

What Is scanpst.exe?

Scanpst.exe (also called the Inbox Repair Tool) is a utility that ships with Microsoft Outlook. It diagnoses and repairs corruption in Outlook data files:

  • PST files (Personal Storage Table) — used for POP3 accounts and local archives
  • OST files (Offline Storage Table) — used for cached Exchange/Microsoft 365 mailboxes

The tool checks the internal data structure of the file, identifies inconsistencies, and attempts to fix them. It does not modify the contents of your email messages themselves.

Scanpst.exe Locations by Office Version

The file path depends on your Office version and whether you have a 32-bit or 64-bit installation. Below is the complete reference.

Microsoft 365 (Click-to-Run)

C:\Program Files\Microsoft Office\root\Office16\scanpst.exe
C:\Program Files (x86)\Microsoft Office\root\Office16\scanpst.exe

Office 2021 / Office 2019

C:\Program Files\Microsoft Office\root\Office16\scanpst.exe
C:\Program Files (x86)\Microsoft Office\root\Office16\scanpst.exe

Office 2016

Click-to-Run installation:

C:\Program Files\Microsoft Office\root\Office16\scanpst.exe
C:\Program Files (x86)\Microsoft Office\root\Office16\scanpst.exe

MSI-based installation:

C:\Program Files\Microsoft Office\Office16\scanpst.exe
C:\Program Files (x86)\Microsoft Office\Office16\scanpst.exe

Office 2013

C:\Program Files\Microsoft Office\Office15\scanpst.exe
C:\Program Files (x86)\Microsoft Office\Office15\scanpst.exe

Office 2010

C:\Program Files\Microsoft Office\Office14\scanpst.exe
C:\Program Files (x86)\Microsoft Office\Office14\scanpst.exe

Office 2007

C:\Program Files\Microsoft Office\Office12\scanpst.exe
C:\Program Files (x86)\Microsoft Office\Office12\scanpst.exe

Quick Way to Find It

If you are unsure which version or installation type you have, open a Command Prompt or PowerShell window and run:

dir "C:\Program Files*\Microsoft Office" /s /b | findstr /i scanpst.exe

Or in PowerShell:

Get-ChildItem -Path "C:\Program Files*" -Recurse -Filter "scanpst.exe" -ErrorAction SilentlyContinue | Select-Object FullName

Common Issues That scanpst.exe Fixes

Scanpst.exe can resolve the following problems:

  • “The file .pst is not a personal folders file” — Indicates header corruption in the PST file.
  • “Errors have been detected in the file .pst” — General corruption detected by Outlook at startup.
  • Outlook hangs or crashes on startup — Often caused by a damaged default PST or OST file.
  • Emails stuck in the Outbox — Can happen when the PST structure is damaged in the send/receive area.
  • Cannot move or delete items — Folder-level corruption preventing normal operations.
  • Missing folders or messages — Structural corruption hiding parts of the data tree.

Step-by-Step Repair Process

Step 1: Close Outlook Completely

Scanpst.exe cannot repair a file that is in use. Close Outlook and confirm it is not running in the background:

  1. Close Outlook.
  2. Open Task Manager (Ctrl + Shift + Esc).
  3. Look for OUTLOOK.EXE in the Processes tab. If it is there, right-click it and select End Task.

Step 2: Back Up Your PST File

Before running any repair, copy the PST file to a safe location. The default PST file location depends on your Windows version:

Windows 10/11:

C:\Users\<username>\Documents\Outlook Files\

Older Windows versions:

C:\Users\<username>\AppData\Local\Microsoft\Outlook\

If you do not know where your PST file is located, open Outlook (before it crashes, if possible) and go to File > Account Settings > Account Settings > Data Files tab. The path is listed there.

Step 3: Run scanpst.exe

  1. Navigate to the appropriate folder from the version table above.
  2. Double-click scanpst.exe to launch it.
  3. Click Browse and select the PST (or OST) file you want to repair.
  4. Click Start to begin the scan.

Step 4: Review the Scan Results

After the scan completes, the tool will report one of the following:

  • No errors were found — The file is structurally intact. Your problem lies elsewhere.
  • Errors were found — The tool will show a summary. Check the “Make backup of scanned file before repairing” checkbox (enabled by default), then click Repair.

Step 5: Run the Repair Multiple Times If Needed

For severely damaged files, a single pass may not fix everything. Run scanpst.exe again after each repair. Repeat until the tool reports no errors found.

Step 6: Recover Items from the Lost and Found

After a repair, open Outlook. You may see a folder called Lost and Found (or Recovered Personal Folders) in the folder list. This folder contains items that the tool could not place back into their original location. Move them to the appropriate folders manually.

When scanpst.exe Is Not Enough

Scanpst.exe has limitations. It will not help in these situations:

  • The PST file is too severely damaged — If the file header is completely destroyed, the tool cannot read it at all. Third-party PST recovery tools (such as Stellar Repair for Outlook or Kernel for Outlook PST Repair) may be able to extract data.
  • The file exceeds the size limit — Outlook 2002 and earlier had a 2 GB limit on PST files. If the file grew past that, it requires a special truncation tool before scanpst.exe can work.
  • OST file corruption with Exchange — For OST files, it is often faster to delete the OST file and let Outlook re-create it by re-syncing with the Exchange server, rather than attempting a repair.

Creating a New Outlook Profile

If scanpst.exe repairs the file but Outlook still misbehaves, the Outlook profile itself may be damaged. Create a new profile:

  1. Open Control Panel > Mail (or search for “Mail” in the Start menu).
  2. Click Show Profiles.
  3. Click Add, give the new profile a name, and configure your email account.
  4. Set the new profile as the default.
  5. Re-add your repaired PST file via File > Open & Export > Open Outlook Data File.

Preventing PST Corruption

To minimize the risk of PST file corruption in the future:

  • Do not exceed recommended PST size limits. Microsoft recommends keeping PST files under 50 GB for Outlook 2010 and later. Smaller is better for performance and reliability.
  • Do not store PST files on network drives. Microsoft does not support PST files over a network connection. This is the single most common cause of PST corruption.
  • Use a UPS or battery backup. Power loss during a write operation is a frequent cause of corruption.
  • Keep Outlook updated. Microsoft regularly patches bugs that can cause or worsen file corruption.
  • Compact PST files periodically. Right-click the PST in the Outlook folder list, select Data File Properties > Advanced > Compact Now.