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. It supports all Outlook versions and has no file size limitations, making it a comprehensive solution for recovering inaccessible OST data. I don’t have an answer to this other than to voice my suspicion that it is likely due to new Microsoft updates (windows and office). FixTechGuide fix for stuck folders 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. Change the Outlook sync settings to only keep a limited amount of mail off-line. If you only keep 6 or 12 months offline that will reduce the OST size significantly.

Repair Outlook Data Files (.pst and .ost)

This is all most people will need, searching for older items will be slower but for daily use items it will still be quick. As you close them, lead to the folder and right-click on the OST file. Once you re-open Outlook, your OST file is automatically recreated or rebuilt. If your hard drive goes through any physical damage, it will damage the data across it too. A bad sector or corrupted hard drive can cause OST inaccessibility.

Outlook - OST file recurring corruption

Although the repair process might recreate some of the folders, they may be empty. The rebuild Outlook data file quickly Lost and Found folder contains any folders and items recovered by the repair tool that Outlook can't place in their original structure. You can use the Inbox Repair tool (SCANPST.EXE) to diagnose and repair errors in your Outlook data file.

• Get your OST rebuilt properly with the help of the available techniques.
• There may be items in the backup file that you might be able to recover that the Inbox Repair tool couldn't.
• You could Right-click the Start button, and click Run, type Outlook.exe /safe, and click OK.
• Click the "Data Files" tab on the window and select your respective OST file.
• Confirmed user can log on to OWA (Office 365 webmail) without issue.
• Click the "Open File Location" button to lead to the folder automatically.

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

Fwiw, responding to my original post and how we addressed it for this user - we ended up creating new Outlook profile and limiting the amount of cached mail to 2 years. If the OST still gets corrupted when you have reduced the size there is something in the mailbox causing the problem. You must re-select "Account Settings" when it opens across a drop-down menu. There, lead into the "Data Files" tab and select your OST file. After selecting the file, click on "Open File Location" to redirect to the folder.

Method 4: Use OST Repair Tool

Only way to restore Outlook 2016 (Windows) functionality was to create a new profile; this worked, and a new OST file was created. On the next screen, access the "Find File" option if you are unaware Office 365 Sync Errors Fix of the location. If you know the location, click on the "Add File" tab and browse it.