OST file is created by MS Exchange Server in a local Windows Server. It is created in the same drive location of your Outlook PST files. When link between MS Outlook and Exchange mail server could not be established due to various reasons, Outlook mailboxes of mail server are saved in Offline folders or OST files. Each OST file contains a single Outlook user mailbox and allows a user to access emails in offline mode.
Corruption issues of OST file
When MS Outlook reconnects with MS Exchange Server, changes saved in an OST file get transferred into Outlook PST file. However, long disruption of internet services on MS Exchange Server leads to OST file corruption. Corrupt OST files fail to synchronize with a mail server and as a result, outlook users cannot use their mail accounts on that server. You’ll see various error messages on your computer screen in the event of OST corruption:
- Unable to expand folder
- Unable to expand folder
- Errors have been detected in the File Outlook.OST
- Outlook.OST is in use and could not be accessed
Inbuilt data recovery options
If your computer system is running on Windows XP, then you can create a new Outlook profile for your Exchange mailbox:
- Click on Start> Control Panel>Mail
- Press “Show Profiles” button to view the existing Outlook profile
- Remove all existing Outlook profiles from the display box
- Press “Add” to create new Outlook user profile
- Type the new Outlook profile name and click “Ok”
- Tick on “Manually Configure server settings or additional server types” box and press “Next” button
- Select “Microsoft Exchange Server” email service
- Type Exchange Server address and your user name
- Uncheck the “Use Cached mode” box and press “Next” to make a new Outlook profile
- Restart your Outlook mailbox
With this step, you can access your Outlook mailbox on Exchange Server after internet services resumes. However, data saved by Outlook user during offline period will not appear in your new Outlook mailbox.
Another inbuilt option is scanpst.exe that can fix minor corruption issues of OST as well as PST files. This inbox repair utility is located in the local MS Office folder of your system. You can find the tool from Windows Search file and folder box.
You must use external OST recovery software in the following conditions:
- Badly damaged Hard disk
- Crash of MS Exchange
OST to PST conversion tool
OST to PST conversion software can fix both minor and severe corruption levels of OST folders. It recovers and restores inaccessible, deleted or damaged Outlook profiles from the corrupt OST files. Recovered Outlook mailbox data is saved by this utility in PST files.
With the help of OST to PST conversion tool, one can quickly retrieve mailbox folders such as inbox, sent items, deleted items, drafts, journals and contacts from corrupt OST files. This tool also supports email recovery from password protected OST files. You can also save recovered Outlook data in different file formats such as .PST, .EML, .DBX and .MSG.
OST to PST conversion software displays all recovered mailbox folders in a preview list before saving at specific system folder. It supports different versions of MS Outlook, Outlook Express and MS Exchange Server.
You cannot access your Outlook profile or mailbox on Exchange Server in the event of OST file corruption. You can manually create a new Outlook profile for Exchange Server from local Windows Server. Alternatively you can also use scanpst.exe tool of MS Outlook to recover mailbox data from corrupt OST file. For severe corruption issues such as crash of Exchange Server, you must use a smart data recovery tool such as OST to PST conversion tool. This tool saves recovered emails and email folders in .PST file format.