To repair an Outlook data file in Windows 11, close Outlook, make a copy of the affected file, open Microsoft’s built-in SCANPST.EXE (Inbox Repair Tool), select the .pst file, run Start, and choose Repair if errors are reported. Microsoft cautions that several passes may be necessary and that some content may remain unrecovered.
The procedure applies to desktop Outlook for Microsoft 365, Outlook 2024, Outlook 2021, Outlook 2019 and Outlook 2016. Microsoft does not publish a separate Windows 11-only version of the workflow.
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What SCANPST.EXE does
SCANPST.EXE is Microsoft’s Inbox Repair Tool. It diagnoses and repairs structural errors in local Outlook data files, primarily Personal Storage Table files with the .pst extension. A PST can contain messages, calendar items, contacts, tasks and archived folders stored on your computer.
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A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11The tool is intended for a damaged data file, not for general Outlook configuration problems. It may find broken folder indexes or other file-structure errors, then rebuild portions of the file. It cannot promise recovery of every item, particularly when data has been permanently deleted or the file is severely damaged.
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Check whether you have a PST or an OST
Before running a repair, identify the file type. The correct next step depends on whether the file is a standalone archive or a local copy of a server mailbox.
| File | Typical role | Recommended action |
|---|---|---|
.pst |
Local archive, export or POP account data | Back it up and use SCANPST.EXE to scan and repair it. |
.ost |
Offline cache for an Exchange mailbox | Do not treat it like an independent archive. Outlook normally recreates the local cache from the server after the old OST is removed. |
Microsoft states that the Inbox Repair Tool does not connect to or analyze data stored in an Exchange mailbox. If the problem is an Exchange offline cache, preserving the server copy and allowing Outlook to rebuild the OST is generally more appropriate than trying to repair it as a PST.
Prepare safely before scanning
- Exit Outlook completely. A file still held open by Outlook may be locked or changed while SCANPST is working.
- Make a separate copy of the original PST. Store the copy on another local drive or an external drive. Work from the original only after you have a fallback copy.
- Confirm available disk space. SCANPST creates a backup and may need temporary working space, so the drive containing the file should have room for another copy.
- Note the file’s current location and name. This makes it easier to identify the correct file if several accounts or archives are configured.
- Close other Outlook-related windows. End Outlook and wait a few seconds before starting the repair utility.
Find the Outlook data file in Windows 11
If you do not know which PST is affected, open Outlook and use File > Account Settings > Account Settings > Data Files. The list shows each configured data file and its path. Record the path, then close Outlook before continuing.
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If Outlook cannot open, search File Explorer for *.pst. Do not select a file solely because its name contains “Outlook”; compare the path and file size with the account or archive you are troubleshooting.
Locate and open SCANPST.EXE
The executable is installed with desktop Office. On common Office16 installations, check these locations:
C:Program Files (x86)Microsoft OfficerootOffice16SCANPST.EXEC:Program FilesMicrosoft OfficerootOffice16SCANPST.EXEC:Program Files (x86)Microsoft OfficeOffice16SCANPST.EXEC:Program FilesMicrosoft OfficeOffice16SCANPST.EXE
The first two paths are common for Click-to-Run installations; the latter two may occur with MSI installations. The folder name can still be Office16 on newer supported Outlook releases. If none of these paths exists, press the Windows key and search for SCANPST.EXE, or browse the Microsoft Office installation folders in File Explorer.
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Run the repair, step by step
- Close Outlook. Check Task Manager if Outlook appears to remain open. End only a clearly stalled Outlook process after allowing normal shutdown time.
- Start SCANPST.EXE. Double-click the executable. If Windows displays a security prompt, verify that you opened the copy from the Office installation folder you located.
- Select the PST. In the Inbox Repair Tool, choose Browse, navigate to the path recorded from Outlook’s Data Files page, select the affected
.pst, and choose Open. - Start the scan. Select Start. The utility checks the file and reports whether it found inconsistencies.
- Keep the backup option enabled. Before repairing, note the backup-file location shown by the tool. Do not overwrite your separate manual copy.
- Choose Repair when errors are found. Let the process finish without opening Outlook or moving the file. Large PSTs can take time, and interrupting the process can leave the file in a less usable state.
- Run another pass if needed. Microsoft says SCANPST may need to be run several times before it reports no remaining errors. Close the tool, reopen it, select the same PST and repeat the scan-and-repair cycle.
- Test Outlook. Open Outlook after the repair completes. Check the folders that previously produced errors, then send or receive a test message if the file belongs to an active account.
What to do with recovered folders
After a repair, Outlook may show folders named Recovered Personal Folders or Lost and Found. These folders are evidence that SCANPST recovered items without being able to restore the original folder hierarchy completely.
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- Open each recovered folder and identify messages, appointments, contacts or attachments you still need.
- Create the correct destination folders in Outlook before moving items, especially if the original hierarchy is confusing.
- Move recovered items in small groups and allow Outlook to finish synchronizing or indexing between groups.
- After verifying the contents, keep the original backup and the repaired PST until you are certain nothing else is needed.
Some items may remain missing, duplicated or unreadable. A successful completion message means the file structure was processed; it does not establish that every original item was recovered.
Recover additional items from the SCANPST backup
During repair, SCANPST creates a backup in the original file’s folder with the same base name and a .bak extension. For example, a file named Outlook.pst may produce Outlook.bak.
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If the repaired PST opens but some content is absent, preserve the original .bak and make a copy before experimenting. With Outlook closed:
- Copy the
.bakfile to a separate working folder. - Rename the copy so its name ends in
.bak.pst, such asOutlook.bak.pst. Keep the original backup unchanged. - Open Outlook and use File > Open & Export > Open Outlook Data File to open the renamed copy.
- Inspect its folders and move any additional usable messages or other items into a clean Outlook data file or the repaired PST.
This method is useful only when the backup file still contains readable data. It cannot restore a PST that was permanently deleted, overwritten or corrupted beyond what the backup preserves.
If SCANPST finds errors but Repair fails
Run repeated passes without replacing your backups
Make sure you are scanning the intended PST and that Outlook is closed. Run another pass, but always retain the original PST, your manual copy and the .bak created by the previous attempt. Never delete all versions while trying to obtain a clean scan.
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Check whether the file is changing or growing
If the PST is stored on a network share, removable drive or synchronized folder, copy it to a local drive before repair. Work from one stable copy so another program cannot change the file during the scan.
Try opening the repaired file separately
If your normal Outlook profile still reports an error, open the repaired PST as an additional data file rather than replacing the profile immediately. This distinguishes a damaged file from a profile or account problem.
Repair the Office installation when the utility will not start
If SCANPST.EXE itself will not launch, closes immediately or is missing from every Office folder, use Windows’ installed-app controls to repair the Microsoft Office or Microsoft 365 installation. After the Office repair completes, locate SCANPST.EXE again and repeat the procedure with your preserved PST copy.
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Repeated scans that produce different results, a file that cannot be copied, or widespread unreadable content are warning signs to stop experimenting on the only original. Preserve all versions and consider a specialist recovery service or a reputable third-party PST recovery product. The Microsoft utility has hard limits, and no recovery method can guarantee restoration from severe corruption.
When an OST should be rebuilt instead
An Exchange OST is a local cache, not the authoritative mailbox. If Outlook reports that the OST is damaged but the mailbox remains available on the Exchange server, close Outlook, locate the OST shown in the account configuration, and rename or remove the local cache only after confirming that all recent mail, calendar and contact changes have synchronized to the server. Starting Outlook then allows it to create a new OST and download the mailbox again.
Do not use this approach for a standalone PST archive: deleting a PST removes the only local copy of its contents unless you have a separate backup.
Quick Recap
Decision checklist
- Local PST archive: back it up, run SCANPST, repeat the repair if necessary, and inspect recovered folders.
- Exchange OST cache: verify server synchronization and allow Outlook to recreate the cache instead of treating it as a PST.
- Repair completed but folders are incomplete: inspect Recovered Personal Folders, Lost and Found, and the renamed
.bak.pstcopy. - SCANPST will not run: repair the Office installation, then retry from a preserved copy.
- Severe or worsening corruption: stop making changes to the original and escalate with every backup and log you have.
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