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 - Corrupt OST

Confirmed user can log on to OWA (Office 365 webmail) without issue. Upon starting Outlook, error message displayed is "Errors have been detected in the file ," then prompt appears work offline mode stuck to locate (not fix) the OST file. Outlook 2016 connecting to Office 365 E3, mailbox size ~55GB and Outlook reghack effected to allow for ~80GB OST. If your computer faces unnecessary power outages during a process, it can be damaging. When Outlook is running and is halted in such a way, it can damage the OST file.

How to recover OST files

You can check the location of your Outlook Data Files in Outlook.

• While it is your go-to solution, it provides exceptional repair services.
• This can be done with the help of PST files, another Outlook data file form.
• Open the OST file as per the location provided in the table.
• There, turn on the option of "File Name Extensions" to display extensions.
• While this is an effective model, the discussion would revolve around all possibilities.
• If your hard drive goes through any physical damage, it will damage the data across it too.
• The question mentioned above is thus definite in such a case.
• You must re-select "Account Settings" when it opens across a drop-down menu.

How to Fix Corrupted OST Files

Perfectly repair and recover corrupted Outlook PST & OST files. 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.

Part 3: How to Rebuild OST Files?

If anyone can get an answer from microsoft on this issue I’d appreciate it. Any MS techs can contact me if they need further information or analysis. I’ve created a ticket today with Rackspace to see if their other customers are having this issue but I’m not hopeful on hearing back from them. Only way to restore Outlook 2016 (Windows) functionality was to create a new profile; this worked, and a new OST file was created.





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. The solve Office 365 mailbox sync delays question mentioned above is thus definite in such a case.



Even with the reg hack in place, I’ve found that ost files over 50gb tend to corrupt and become unusable with regularity. OST file corruption is a common problem faced by Outlook users like you. While you seek to counter this problem, you look for effective techniques. Although there are many methods to try, a few are productive. One such method is to rebuild the OST file across Outlook. The functionality is diverse, and it can be approached in multiple directions.

I can't repair corrupted Outlook .ost file

You might be working on something important across it when it guide to Office 365 sign-in errors 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. This article offers to rebuild the OST file without putting you in any difficulty.

You can create a new Outlook Data File and drag the items in the Lost and Found folder into the new data file. After you've moved all the items, you can remove the Recovered Personal Folders (.pst) file, including the Lost and Found folder. To create a new Outlook Data File, go to Create an Outlook Data File. If you're using an Exchange email account, you can delete the offline Outlook Data File (.ost) and Outlook will recreate the offline Outlook Data File (.ost) the next time you open Outlook.