How to Repair an Outlook Data File With ScanPST

When Outlook refuses to open, crashes on launch, or shows a message like 'The file [filename].pst cannot be opened' or 'The data file was not closed properly,' the likely culprit is a corrupted data file. Microsoft ships a free repair tool for this — ScanPST.exe, also called the Inbox Repair Tool — that diagnoses and fixes most logical errors in a PST or OST file without data loss. The main challenge is finding it, because it is buried deep in the Office installation folder and is not in the Start menu.

This guide covers exactly where to find ScanPST.exe on every version of Outlook, how to run it safely, and what to do when it cannot finish the job.

Before you start: back up the file and know your file type#

Two things matter before you touch anything. First: back up the data file. ScanPST creates its own backup before it repairs, but that backup disappears when you close the tool. Copy the PST to a safe location — a second drive or a cloud folder — before you run a scan. If the repair introduces new problems, you still have the original to try again from.

Second: know which type of file you have. Outlook uses two formats. A PST (Personal Storage Table) is a local archive file that lives on your hard drive. An OST (Offline Storage Table) is a local cache of a mailbox hosted on Exchange, Microsoft 365, or an IMAP server. The repair path is different for each.

For an OST file, the fastest fix is usually not to repair it at all. Because the OST is a local copy of server data, you can close Outlook, delete the OST file, and reopen Outlook — it recreates the cache from the server automatically, with no loss of mail. ScanPST works on OST files, but running a full scan and repair cycle is slower than letting Outlook rebuild. Reserve ScanPST for PST files and for OST files where the rebuild is not an option.

How to run ScanPST.exe to repair a corrupt Outlook data file#

Once you have backed up the data file and confirmed Outlook is fully closed, work through the steps below in order. The tool is straightforward, but running it on an open file produces unreliable results — close Outlook first, before anything else.

1. 1

   Close Outlook completely

   Exit Outlook and confirm it is not running in the background. Open Task Manager (Ctrl + Shift + Esc), look for OUTLOOK.EXE in the Processes tab, and end it if it is still there. ScanPST cannot reliably repair a file that is locked by a running process.

2. 2

   Locate ScanPST.exe for your Outlook version

   The path depends on your Outlook version and whether Office is installed as 32-bit or 64-bit. The platform differences table in the next section lists the exact path for each version. The quickest shortcut on any Windows machine is to open File Explorer, paste the path into the address bar, and press Enter. If you are not sure which version you have, open Outlook, go to File > Office Account > About Outlook, and read the version number and architecture from the dialog.

3. 3

   Open ScanPST.exe and browse to the data file

   Double-click SCANPST.EXE. In the dialog that opens, click Browse and navigate to the PST file you want to repair. The default location for PST files on Windows 10 and 11 is C:\Users\[username]\AppData\Local\Microsoft\Outlook\. The AppData folder is hidden by default — paste the path directly into the address bar or enable Show hidden items in File Explorer's View settings.

4. 4

   Start the scan

   Click Start. ScanPST reads through the file and checks its internal structure for errors. The scan duration depends on file size — a 2 GB PST takes a few minutes; a 20 GB file can take considerably longer. Let it run without interruption.

5. 5

   Review the results and click Repair

   When the scan finishes, ScanPST reports the number of errors found. If errors are present, a Repair button appears. Before clicking it, confirm the checkbox to make a backup of the scanned file is checked (it is checked by default — leave it checked). Then click Repair. The tool fixes the logical structure of the file and moves any unrecoverable items into a Recovered Items folder inside Outlook.

6. 6

   Run the scan a second time

   Repairing errors can expose additional underlying problems that were hidden behind the first set. Once the first repair completes, run ScanPST again on the same file. If the second scan finds no errors, the file is clean. If it finds more, repair again. Most files need no more than two or three passes.

7. 7

   Reopen Outlook and check Recovered Items

   Start Outlook. If a Recovered Items folder has appeared inside your PST, open it and review the contents — it holds items that were in damaged sections of the file. Move anything you want to keep into a normal folder, then delete Recovered Items. Your inbox should now open and sync normally.

Where is ScanPST.exe? Paths for every Outlook version#

Microsoft installs ScanPST.exe inside the Office program folder, not in an obvious location. The exact path depends on your Outlook version and whether Office is 32-bit or 64-bit. The table below covers every version still in active use. If the path does not exist on your machine, your Office installation may be in a non-default directory — use Windows Search and type SCANPST.EXE to find it wherever it landed.

PST vs OST: repair or rebuild?#

The decision between running ScanPST and taking a different path is simpler than most guides make it sound. If you have a PST file with errors, ScanPST is the right first step. If you have a corrupt OST and the mailbox is still on the server, delete and rebuild — do not waste an hour running ScanPST on data you can re-download for free.

What to do when ScanPST does not fix the errors#

ScanPST handles most logical corruption — damaged file structure, incomplete writes, bad headers. It cannot recover from physical disk errors, a truncated file, or severe corruption where the internal table is destroyed. If the tool keeps reporting errors after two or three passes, or if Outlook still crashes after a successful repair, work through the escalation steps below.

• Run ScanPST again on the repaired file. Each pass surfaces the next layer of errors. Most files are clean within three passes. If errors persist after four passes, the corruption is too deep for ScanPST alone.
• Check the drive for physical errors. Open an elevated Command Prompt and run chkdsk C: /f /r on the drive where the PST is stored. A failing drive produces corruption faster than any repair tool can keep up with — fix the drive first.
• Import into a new PST. Create a new data file in Outlook (File > Account Settings > Data Files > Add), then use File > Open and Export > Import/Export to import from the repaired PST into the new one. Outlook often recovers items during an import that ScanPST cannot reach directly.
• Create a new Outlook profile. A corrupted profile configuration, not the data file itself, is sometimes the real cause of crashes. Go to Control Panel > Mail > Show Profiles > Add, create a new profile, and reconnect your account. If Outlook opens fine in the new profile, the old profile configuration was the problem.
• Use the Microsoft Support and Recovery Assistant. Microsoft offers a free diagnostic tool that automates several repair steps and can fix configuration errors ScanPST does not touch. Download it from the Microsoft Support site.
• Accept partial recovery and move on. If the PST is an old archive rather than an active mailbox, import what the damaged file allows, accept that severely corrupted blocks cannot be recovered, and archive future mail in smaller files so one corruption event does not take everything down.

A faster way to stay ahead of Outlook data file problems#

Running ScanPST is the right fix when a PST file breaks. But the deeper problem for many people is that managing a large local PST — archiving into it, keeping it under size limits, remembering to back it up — adds overhead that compounds over years into exactly the fragile setup this guide describes. If you find yourself here regularly, the issue is less the corruption event and more the maintenance burden of an ever-growing local data file.

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