You encounter a large numbers of conflict items in your offline folder (.ost) file.

Precise Explanation:

This error means your OST file is corrupt or damaged.


To solve this error and prevent data loss, please follow the steps below:

  1. Close Microsoft Outlook and other applications that may access the OST file.
  2. Find the OST file that causes the error. You can determine the file location based on the property displayed in Outlook. Or use the Search function in Windows to search for the OST file.
  3. Recover the offline data in the OST file. The OST file contains offline data, including the emails and all other items, in your Exchange mailbox, which are of the most importance to you. To salvage these data, you must use DataNumen Exchange Recovery to scan the corrupt OST file, recover the data in it, then save them into an error-free Outlook PST file so that you can access all the emails and items within Outlook easily and efficiently.
  4. Backup the original OST file. For the sake of security, you’d better backup it.
  5. Rename or delete the original OST file.
  6. Fix the error. Make sure the Exchange email account settings in Outlook are correct, and Outlook can connect to your Exchange server successfully. Then restart Outlook and send/receive your emails on the corresponding Exchange mailbox, which will make Outlook create a new OST file automatically and synchronize its data with the mailbox on the Exchange server.If this method doesn’t work, then your current mail profile is incorrect, you have to delete it and create a new one, as follows:
    • 6.1 Close Microsoft Outlook.
    • 6.2 Click Start, and then click Control Panel.
    • 6.3 Click Switch to Classic View if you are using Windows XP or higher versions.
    • 6.4 Double-click Mail.
    • 6.5 In the Mail Setup dialog box, click Show Profiles.
    • 6.6 Select one of the incorrect profile in the list and click Remove to remove it.
    • 6.7 Repeat 6.6 until all incorrect profiles have been removed.
    • 6.8 Click Add to create a new profile and add email accounts according to their settings on the server.
    • 6.9 Start Outlook and re-synchronize your Exchange mailbox, you will find the problem disappear.
  7. Import the data recovered in step 3. After your OST file problem is fixed, keep the new OST file for the Exchange mailbox open, and then open the PST file generated in step 3 with Outlook. As it contains all the recovered data in your original OST file, you can copy required items to your new OST file.