outlook Data File Corruption Issue

Question

Dear Microsoft Support Team,

I am experiencing a critical issue with Microsoft Outlook. Upon launching the application, I receive the following error message:

"Outlook Data File Corruption
Problems were detected with one of the Outlook Data Files currently in use. This process and all other syncing of this file will be shut down automatically in 49 seconds. You need to relaunch Outlook using this file.
If you continue to see this message, select Create New Data File to make a backup copy of your existing Outlook Data File. When you restart Outlook, a new Outlook Data File will be created."

I have attached a screenshot of the error for your reference.

I would appreciate your guidance on how to resolve this issue without losing any of my existing emails or data. Please let me know the next steps or if any diagnostic tools are available to repair the corrupted file.

Thank you for your support.

Answer 1

Hi Abdulrahman Gamal Sayed,

Thank you for posting in Microsoft Community.

I'm sorry for any inconvenience may have caused. Regarding to your description, while I'm not sure which troubleshooting steps you've already tried, but I'd recommend a few which may help you:

1. You can use the Inbox Repair Tool (ScanPST.exe) to fix minor corruption in .pst files by following these articles:

• Repair Outlook Data Files (.pst and .ost) - Microsoft Support
• How to repair personal folder file (.pst) - Outlook | Microsoft Learn

Please take some time reading the content of this article to avoid further complications.

2. You can try to create a New Outlook Profile if the corruption persists:

• Go to Control Panel > Mail > Show Profiles.

• Click Add to create a new profile.
• Reconnect your email account.
• Launch Outlook with the new profile

3. You can try to delete and recreate .ost File by

• Navigate to %localappdata%\Microsoft\Outlook
• Delete the .ost file
• Restart Outlook, it will recreate the file automatically.

Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution. 

I hope this helps. If you have any difficulties, please don't hesitate to let me know.

Best Regards,
Mia - MSFT | Microsoft Community Support Specialist.

Answer 2

hi Mia-Tr,
**"I already have an .ost file that exceeds 100 GB—it's currently about 115 GB i want solution which i when and outlook cant open ."**Best Regards,

Answer 3

Hi Mohamed Ismail,

Thank you for your update, and I apologized for my late response.

Could you kindly confirm whether your account is a Microsoft 365 Exchange account? If so, please be assured that your email data is safe on the Microsoft 365/Exchange server and the .ost file on your computer is just a local copy that has become corrupted due to its excessive size, not your original data.

To fix this and get you back into Outlook, I recommend you create a new Outlook profile to force Outlook to build a fresh, clean .ost file by downloading your data directly from the server.

To create new Outlook profile, you can follow these steps below:

• Close Outlook Classic completely.
• Open the Control Panel, then search for Mail (Microsoft Outlook).
• In the Mail Setup - Outlook dialog box, click Show Profiles....
• Click Add... to create a new profile, then configure your email account within it.
• Set the new profile as default by in the "Mail Setup - Outlook" dialog box, select your new profile under Always use this profile.
• Reopen Outlook and Outlook will start downloading your data from the server and create a new .ost file. This process may take some time depending on your mailbox size and internet speed.
• After Outlook is working normally, you can delete the old 115GB .ost file from %localappdata%\Microsoft\Outlook to free up disk space.

Tip: It’s a good idea to regularly clean up your mailbox on the server (e.g., delete old emails, archive large attachments) to keep your mailbox and .ost file under 50GB for better performance and stability.

I hope this helps, if you have any further update, please don't hesitate to let me know.

Best regards,

Mia - MSFT | Microsoft Community Support Specialist.

Answer 4

Dear Abdulrahman Gamal Sayed,

Good day and I hope you're doing well.

It has been a while and I am writing to see how things are going with this issue. Have you encountered any difficulties, or is there anything else I can assist you with?

Thank you for your valuable time.

Best Regards,
Mia - MSFT | Microsoft Community Support Specialist.