Microsoft Outlook is a proficient email client for Windows users. Information of an Outlook mailbox is stored in two file formats i.e., OST and PST. OST or offline storage table is temporary storage container of MS Outlook and it saves Outlook user mailbox in cached exchange or offline mode. Non-synchronization of OST files with the MS Exchange Server blocks access of Exchange mailboxes to users.
There are several reasons behind non-synchronization or corruption of OST files such as:
- Virus, spyware and Trojan attacks
- Unexpected server shutdown
- Corrupt hard drive
- Fault in LAN cable
- 2 GB storage limit of MS Outlook
- Shutdown of MS Windows
- Hardware failure
- Dial up internet connection
- Accidental deletion of the Exchange mailbox
OST Corruption Errors and Manual Recovery Options
OST files of MS Outlook become inaccessible due to set of reasons notably virus and spyware intrusion, dirty shutdown of MS Exchange Server and others. Users cannot access their exchange mailbox as an immediate impact of OST file corruption.
Corrupt or inaccessible OST table show different error messages as listed below:
- Unable to expand the folder
- The file xxxx.OST is not an offline folder file
- Outlook.OST is in use and could not be accessed
There are three ways of recovering OST file or Exchange mailbox manually:
- Creation of a new MS Outlook profile on the Exchange Server
- Mailbox recovery from the MS Exchange backup folder
- Scanost.exe tool to recover inaccessible Exchange mailbox data
Creation of a new user profile corresponding to the Exchange email account in many situations proves handy in resolving OST corruption issues. You can create a new Outlook profile by following the steps mentioned below:
- Go to Control Panel and click “Mail”
- Right click on “Show profiles” that will show existing Outlook profiles in your system
- Click “Add” button to create a new Outlook profile and press “Ok”
- Tick “Manually configure server settings or additional server types” checkbox and press “Next”
- Select “Microsoft Exchange” option and press “Next”
- Type domain name of your Exchange Server and press “Next”
- Click “Finish” and restart MS Outlook
Alternatively you can also restore inaccessible OST file or Exchange mailbox from the Backup folder. Minor issues in the OST file can be fixed with the help of OST integrity tool or scanost.exe of MS Outlook. However, except Exchange backup file, all manual recovery options fails to recover severely damaged or large OST files.
RecoveryFix for OST
If Exchange backup file too becomes unreadable, then the most ideal solution you can opt is usage of third party software such as RecoveryFix for OST. It can recover multiple corrupt OST files of a network in a single cycle. Convert OST to PST tool extract entire exchange mailbox from a corrupt OST file and save the extracted mailbox in PST format. OST to PST converter also provides option to save the recovered user mailbox items in other file formats such as DBX, MSG and EML. Evaluation version of OST to PST tool can be used as a freeware that show all recovered mailbox items in a preview structure. To save the recovered Exchange mailboxes in a specific file format, full version must be installed on a user system.