There may be items in the backup file that you might be able to recover that the Inbox Repair tool couldn't. Open the OST file as per the location provided in the table. As you open it across the File Explorer, lead to the "View" menu from the top. There, turn Fix Outlook and Office365 Sync Issues on the option of "File Name Extensions" to display extensions.

Repair Outlook Data Files (.pst and .ost)

Click the "Data Files" tab on the window and select your respective OST file. Click the "Open File Location" button to lead to the folder automatically. Outlook OST is directly connected and synchronized to the email client. If the problems occur across the synchronization of the OST file, it would be damaging. The file would get inaccessible and won't update in any case. To the ones that said 50Gb are more than enough for most people,… well we are in 2020 & I can assure you that more than half of the accounts we manage are way above 50Gb, close to 100Gb actually.

Outlook - OST file recurring corruption

The functionality is diverse, and it can be approached in multiple directions. When the case comes to rebuilding the OST file, there are several things to look out for. If Office 365 Sync Errors Fix you can open the original Outlook Data File, you might be able to recover additional items. The Inbox Repair tool creates a backup file with the same name as the original, but with a .bak extension, and saves it in the same folder.

• Once you re-open Outlook, your OST file is automatically recreated or rebuilt.
• Although there are many methods to try, a few are productive.
• The Lost and Found folder contains any folders and items recovered by the repair tool that Outlook can't place in their original structure.
• Further, the saved PST file could be accessed at any time by importing it in the Outlook profile.
• To execute this, you need to have a good tool with yourselves.
• Any MS techs can contact me if they need further information or analysis.
• You might be working on something important across it when it happens.
• Only way to restore Outlook 2016 (Windows) functionality was to create a new profile; this worked, and a new OST file was created.

What are the major Reasons of OST Corruption and how to Fix it

When Outlook is running and is halted in such a way, it can damage the OST file. You might be working on something important across it when it happens. As you said Outlook E3 licenses should support at least 100GB of data & there’s no excuse why it can’t support OSTs above 50GB when they offer twice that space. In addition, you could open outlook in safe mode, maybe some add-ins affect the outlook. You could Right-click the Start button, and click Run, type Outlook.exe /safe, and click OK. Refer to this blog Solutions To Fix Error – "Errors Have Been Detected In The File Xxx.Ost" Solutions To Fix Error – "Errors Have Been Detected In The File Xxx.Ost" for the solution to this OST error.

Method 4: Use OST Repair Tool

In certain cases, you must go for other methods to recover the data across OST files. If the respective file is not rebuilding from the above methods, there are other ways to get its data. This can be done with the help of PST files, another Outlook data file form. While they act as the basic backup data file for the user, the OST file solve Office 365 mailbox sync delays can be easily converted to this form. Also, I forgot to mention that normally when the OST is corrupted you normally delete the file and recreate it.