I’ve used the repair tool when this started and it did not really repair the file. I used the following combination of techniques to get the user working. In the mailbox not updating on IMAP Folder Pane, you might see a folder named Recovered Personal Folders that contains your default Outlook folders or a Lost and Found folder.

Repair Outlook Data Files (.pst and .ost)

An Outlook data files are designed to safely handle max space 50GB in Outlook 2010 to 2019 and Office 365 by default. You can try syncing outlook file 6 to 12 months or through archiving email using retention policy, could be a better way to protect the .ost size from corrupt. As it is converted, you can easily view the contents of the data file.

Outlook - OST file recurring corruption

You surely won't be disappointed with the results of rebuilding OST. As you change the extension, relaunch Outlook Repair Outlook Profile Online to rebuild your OST file. The first solid question that comes to mind is whether OST files are rebuildable. We are aware that OST files are directly connected to the Outlook email.

• If you know the location, click on the "Add File" tab and browse it.
• When the case comes to rebuilding the OST file, there are several things to look out for.
• You must re-select "Account Settings" when it opens across a drop-down menu.
• Find the .ost file that the error message reported to have errors, and then delete it and open outlook, it will recreate a new .ost file.
• The WebbyAcad OST Recovery Tool offers advanced features to fix damaged OST files and convert them to PST, EML, MSG and other formats while preserving folder hierarchy and metadata.
• Although the repair process might recreate some of the folders, they may be empty.
• Find solutions to common problems or get help from a support agent.
• As it is converted, you can easily view the contents of the data file.

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

This article has provided an overview of how you can quickly rebuild an OST file. With the methods and Wondershare Repairit for Email, you can make cohesive use of the available resources. Get your OST rebuilt properly with Outlook OST vs PST repair the help of the available techniques.