Microsoft Outlook is one of the components of Microsoft Office Suite by which we can send and receive emails. It also provides the facility to store other items such as tasks, calendars, journals, etc. Outlook stores Outlook Data Files in two file formats: Personal Storage Table (.pst) and Offline Storage Table (.ost). Your items which include emails, tasks, calendars and journals are delivered to and saved on the mail server when you use Microsoft Exchange account. OST data file allows you to work on your messages even if you are offline on the mail server. You can keep a local copy of your data files on your system in OST format by configuring Outlook. Thus, you can use Cached Exchange Mode when you are not connected to exchange computer. When connection is available, the .ost file gets synchronized with Exchange computer.
By the help of offline folders, you can modify, add and delete data files or contents of an offline outbox even if you are not connected to the network. New messages are kept on the server; you can update the folder and its corresponding server after getting connected to the network so that both folders will have identical contents. It is known as folder synchronization. This is the main advantage of OST file format.
OST file is synchronized with the files on the server that runs Exchange. You can re-create this .ost file on new system as the data remains on Exchange Server.
Windows XP: drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook.
Windows Vista and 7: drive:\Users\user\App Data\Local\Microsoft\Outlook
Sometime you may get an error message while synchronizing offline folder in Outlook with mailbox on the server. Sometime your files can be missing from offline folder or from mailbox after synchronizing. If you are not able to open or access OST file, then it may be corrupted or damaged. Corruption occurs due to many reasons which include both software and hardware factors. Software factors include software malfunction, virus attacks, synchronization error and abrupt termination of Outlook. Hardware factors include power failure, hard drive failure and failure in network connection.
There is a built-in repair tool in Outlook that can repair OST file. It is called as OST Integrity Check tool (Scanost.exe). It runs only on .ost files and successfully repairs synchronization error. OST Integrity Check tool can be used after getting connected to your Exchange account. It scans items and mailbox folder.
Transferring Server’s OST files to Outlook is same as converting OST to PST. It can be done by using “Import” function available in Outlook e-mail client. Refer convert OST to PST manually to clear your doubts.
This tool (scanost.exe) is installed in your in your system when you install Outlook. The location of this file is: drive:\Program Files\Microsoft Office\OFFICE12
Follow these steps to Repair OST File using Scanost.exe:
- Close Outlook (if open)
- Find Scanost.exe and then double click on it
- Microsoft Outlook Inbox Repair tool window will be opened
- Select profile which contains corrupt .ost file. If it prompts to connect or work offline, then click connect.
- Select appropriate option
- Click on Begin Scan
- After completion, you will a message “OST repaired successfully”.
Scanost.exe is considered as one of the best manual solutions to repair OST file if the file has synchronization errors or if it has minor corruptions. But sometime the file is severely corrupted or damaged and it cannot be repaired with the help of Scanost.exe file. The only left option is then to use a Third-Party Software. Files can also get corrupted during file system recovery. You should use a good recovery tool otherwise a bad tool will worsen the corrupted file.
OST File Recovery Software is recommended third party tool from software experts. It first scans the OST file and then successfully repair OST file. You can save the repaired OST file in any of the following formats: DBX, MSG, PST, MBOX, EML and archive format. You can try its free demo version and check whether it recovers OST file.