How to repair your Outlook personal folder file (.pst)

Follow these steps to repair your Outlook personal folder file (.pst) by using Inbox Repair tool, and you may also reference Video: How to repair your Outlook Person Folder (.pst) files under the For more information section.

Automatically start the Inbox Repair tool
Manually start the Inbox Repair tool
In the Inbox Repair tool, type the path and the file name of your personal folders (.pst) file or click Browse to locate the file by using the Windows file system, and then click Start.
Note If you do not know where the .pst file is located, follow the steps in How to locate, move, or back up your .pst file.
A screenshot for the Inbox Repair tool.

  • The Inbox Repair Tool may need to be run several times in order to fully repair your personal folder (.pst) file.
  • The Inbox Repair Tool cannot repair every problem that is detected. In some cases, items may not be recovered if they were permanently deleted or corrupted beyond repair.

After you run the Inbox Repair tool, you can start Outlook and recover repaired items. Optionally, you can try to recover additional repaired items from the backup personal folder.

To start, create a new Personal Folders (.pst) file entry in your profile. Then, you can move the recovered items to your new Personal Folders (.pst) file.
  1. Start Outlook. If you use multiple profiles in Outlook, make sure that you select the profile that contains the Personal Folders (.pst) file that you tried to repair.
  2. Press CTRL+6 to turn on Folder List view.
  3. In your Folder List, you should see the following recovered folders:

    Recovered Personal Folders

    Deleted Items
    Sent Items
    Note These recovered folders are usually empty because this is a rebuilt .pst file. You should also see a folder named Lost and Found. This folder contains folders and items that the Inbox Repair Tool recovered. Unfortunately, items that are missing from the Lost and Found folder may be beyond repair.
  4. Create a new Personal Folder (.pst) file in your profile. The steps may be different, depending on which version of Outlook you are running.

    Outlook 2010 and later
    1. Click on the File tab on the ribbon, and then click the Info tab on the menu.
    2. Click the Account Settings button, and then click Account Settings again.
    3. Click the Data Files tab.
    4. Click Add to open the Create or Open Outlook Data File dialog box.
    5. Enter a file name for your new Outlook Data (.pst) file, and then click OK.
    6. You should have a new Outlook Data (.pst) file in your profile.
    Outlook 2007
    Outlook 2003
    Outlook 2002
  5. Drag the recovered items from the Lost and Found folder to your new Personal Folders (.pst) file.
  6. When you have finished moving all items, you can remove the Recovered Personal Folders (.pst) file from your profile. This includes the Lost and Found folder.
  7. If you are satisfied with the information that you recovered, you are finished. However, if you want to try to recover additional information, go to "Recover repaired items from the backup file."

More Information

The Inbox Repair tool (Scanpst.exe) is designed to help repair problems that are associated with personal folder (.pst) files.
The Inbox Repair tool is automatically installed with all English-language Microsoft Outlook installation options depending on your operating system. Learn more about the Inbox Repair tool .
If you can't start the Inbox Repair tool automatically or manually, you may try to repair your Office programs.
Note If you could not open your original Personal Folders (.pst) file before you ran Inbox Repair Tool, the following procedures may not work. If it does not work, then unfortunately, you will be unable to recover any additional information. If you could open the file, the following procedure may help you recover additional items from your damaged Personal Folders (.pst) file.

When you run Inbox Repair Tool, the option to create a backup of the original Personal Folders (.pst) file is automatically selected. This option creates a file on your hard disk that is named "File name.bak" (without quotation marks). This file is a copy of the original File name.pst file with a different extension. If you think that you are still missing items after following the steps in the previous section, you can try to recover additional information from this backup file by following these steps:

Locate the .bak file. It is located in the folder of your original Personal Folders (.pst) file.
  1. Locate the .bak file. It is located in the folder of your original Personal Folders (.pst) file.
  2. Make a copy of the .bak file and give the file a new name with a .pst extension. For example, name the file "New name.pst" (without quotation marks).
  3. Import the New name.pst file that you created in the previous step by using the Import and Export Wizard in Outlook. To do this, follow these steps:
    1. On the File menu, click
      Import and Export.
      Note On Outlook 2010 and later, click the File tab on the Ribbon, click Open, and then click Import.
    2. Click Import from another program or file, and then click Next.
    3. Click to select Personal Folder File (.pst), and then click Next.
    4. Under File to import, click
      Browse, and then double-click your Newname.pst file.
    5. Under Options, click Do not import duplicates, and then click Next.
    6. Under Select the folder to import from, click to select the Personal Folders (.pst) file, and then click to select Include subfolders.
    7. Click to select Import folders into the same folder in, and then select your new Personal Folders (.pst).
    8. Click Finish.
    Note Remember that the backup file was the original corrupted file, and you may find that you cannot recover anything other than what was recovered in the Lost and Found folder. If you cannot import the Newname.pst file into Outlook, unfortunately you have lost all the information that is not in the Lost and Found folder.

How the Inbox Repair tool validates and corrects errors

ScanPST mostly validates and corrects errors in the internal data structures of a .pst file. The .pst file is a database file. Therefore, structures such as BTrees and reference counts, are checked and repaired as necessary. These low-level objects have no knowledge of the upper-level structures, such as messages, calendar items, and so on, that are built upon them.

If ScanPST determines that a specific block of the structure or table is unreadable or corrupted, ScanPST removes it. If that block was part of a specific item in Outlook, the item will be removed when it is validated.

You may not expect this behavior, but the removal of the item is appropriate given the circumstances. Also, this specific kind of situation is rare, and it will always be entered in the ScanPST log file.

At a higher level, the more visible changes that you see involve folders and messages.


ScanPST examines every folder in the .pst and performs the following operations:
  1. ScanPST makes sure that there are the correct tables associated with the folder.
  2. ScanPST checks every row in each table and makes sure that the message or the subfolder exists in the system.
  3. If ScanPST cannot find the message or the subfolder, ScanPST removes the row from the table.
  4. If ScanPST does find the message or the subfolder, ScanPST validates the message or the folder.
  5. If that validation fails, the message or folder is considered corrupted, and it is removed from the table and deleted from the database.
  6. If the validation succeeds, ScanPST does another analysis to make sure that the now-recovered message values are consistent with the values in the table. Corrupted folders are recreated from scratch, if it is necessary. These folders contain no user data.

Most users will be concerned by message operations, because a corrupted item is likely to cause something to be deleted from the .pst file. ScanPST performs the following operations on messages:
  1. ScanPST does some basic validation of attachment tables and recipient tables. This operation resembles how a folder works with the messages in it.
  2. As soon as the recipient table is validated to guarantee recipients that are formatted correctly, ScanPST makes any changes that are required to synchronize these valid recipient table contents to the recipient properties on the message. ScanPST also guarantees that the message's parent folder refers to a valid folder. The following message properties are checked to make sure that they follow valid data formats:

      ScanPST checks that this property exists. If the property does not exist, it is set to IPM.Note.

      Each flag is validated separately.

      This validation resembles the operation for message flags.

      If the submit flags indicate that the message is marked as submitted, this property must exist. If the submit flags do not indicate that the message is marked as submitted, the time is set to Now.

      This property must exist. If the property is not present, a random GUID is generated for it.

      This property must exist. If the property is not present, the time is set to Now.

      This property must exist. If the property is not present, the time is set to Now.

      Sizes are recalculated and compared to stored values. If sizes differ by some delta, the calculated value is written.
    No validation is explicitly done on body-related properties or on subject-related properties, except the implicit low-level validation that this article discusses earlier. The recipient display properties are changed to be consistent with the recovered recipient table. As soon as this operation is complete, other algorithms are run to collect all the orphaned messages and to put them in an Orphans folder.

    For more information about binary trees (btrees), go to the following Microsoft website:


Article ID: 272227 - Last Review: Oct 24, 2016 - Revision: 1

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