How Can I Recover Data from a Damaged OST File When Outlook Cannot Open It?

Khushi Singh 0 Reputation points
2026-08-07T07:33:18.3933333+00:00

Hi everyone,

How can I recover my data from a damaged OST file when Outlook is not opening it?

I was working with Outlook normally, but suddenly I started getting an error that my OST file could not be opened. Everything was working fine the previous day, and I was still able to access my mailbox through Outlook Web Access, so I knew the account was not the main issue.

I first tried some common troubleshooting steps and repair options. I used ScanPST.exe, but it did not solve the problem. Later, I found that ScanPST is mainly designed for PST files and may not properly repair a severely damaged OST file.

I also checked about ScanOST.exe, but it seems that this tool was only available in older Outlook versions and is not available in the latest versions.

After trying these options, I searched for an automated solution and found one suggested through Microsoft community discussions. I decided to try an OST recovery tool to extract data from my damaged OST file.

The automated recovery solution helped me recover my mailbox items and access the important data stored in the OST file. It was useful because I had some locally stored Outlook data that I did not want to lose.

Has anyone else faced a similar damaged OST file issue? What solution worked for you when Outlook could not open the OST file and regular repair methods failed?

Outlook | Windows | Classic Outlook for Windows | For home
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  1. AI answer

    2026-08-07T07:33:43+00:00

    For a damaged .ost file, the supported recovery path depends on whether the data is still on the server or only in the local cache.

    1. If the mailbox is available in Outlook Web Access or on Exchange, rebuild the .ost file.
      • Close Outlook.
      • Go to %localappdata%\Microsoft\Outlook.
      • Find the affected .ost file.
      • Delete it, or rename the extension to .old.
      • Start Outlook again.
      Outlook recreates the offline data file and redownloads mailbox data from the server. This is the recommended resolution for corruption in an .ost file.
    2. If Outlook reports corruption and the file cannot be opened, ScanOST is not the solution in current versions.
      • Scanost.exe is no longer available starting in Outlook 2010.
      • Current guidance is to delete or rebuild the offline Outlook Data File and let Outlook resync from Exchange.
    3. If locally cached content must be preserved, use the Inbox Repair tool only as a limited diagnostic/repair option.
      • Scanpst.exe can scan both .ost and .pst files and try to repair internal file structure.
      • It does not connect to or analyze mailbox data stored on Exchange.
      • For Outlook 2016/2019, one documented location is C:\Program Files (x86)\Microsoft Office\root\Office16 for SCANPST.EXE.
      • Before running it, back up the existing Outlook data file.
    4. If the issue is with a .pst file instead of an .ost file, use SCANPST.EXE.
      • Exit Outlook.
      • Open SCANPST.EXE.
      • Select Browse and choose the .pst file.
      • Select Start.
      • If errors are found, select Repair.
      • After repair, reopen Outlook.
    5. If SCANPST.EXE repairs a .pst and creates a .bak file, additional items may be recoverable.
      • Copy the .bak file.
      • Rename the copy to use a .pst extension.
      • Import it into Outlook with the Import and Export Wizard.
    6. To confirm the data file location in Outlook when Outlook can open:
      • Select File > Account Settings > Account Settings.
      • Open the Data Files tab.

    If the mailbox is still accessible in Outlook Web Access, rebuilding the .ost file is the primary supported method. The main risk is loss of data that exists only in the local offline cache and was never synchronized to the server, so backing up the damaged file first is the safest step.

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