MS Exchange Server and MS Outlook applications collaboratively creates an e-communication environment. MS Exchange server stores mailboxes of all users in a single EDB file i.e. Exchange Database file. For each user’s mailbox a separate profile is created that can be accessed through outlook with different credentials. On every users local system an exact replica of their mailbox is stored in .ost format, this OST file is the offline storage file that gets synchronized with the exchange server mailbox every time you get connect with the Mailbox Server. After proper synchronization the OST file automatically gets converted into PST file that is accessible with Outlook.
But some times the OST file gets corrupted due to reasons like improper synchronization, malicious virus attacks or various other reasons. This corrupted OST file can not be converted automatically into PST file when it get connected with the Exchange Server, and the ost file becomes inaccessible with all its content.
Consider a practical situation, when you try to start MS Outlook and you come across the following error message.
“Cannot open your default email folders. The file *.ost is not an offline folder file.”
Two reasons that may be responsible for this error message are as follows.
1.OST file gets corrupt due to malicious virus attacks or some other file related issues and MS Outlook is not able to recognize the file.
2.When OST file becomes inaccessible i.e. user is unable to access the file with MS Outlook then the error might have occurred while pursuing synchronization
In case, when it is confirmed that damage to ost file results in ost file inaccessibility then one can use ost repair tool and may recover the OST file. But if the OST file becomes unusable due to improper synchronization, then one should convert OST file into PST file to recover the OST file.
OST to PST conversion can be performed easily by using third party convert ost to psttool. Such ost to pst conversion softwares are especially developed to convert the .ost to .pst file. Convert ost to pst tools are capable to convert all the contents of ost file like e mails, contacts, attachments, notes, journals etc. into .pst file, they can also convert the encrypted or password protected ost to pst file. Such tools supports all the latest versions of Windows like Windows 7, Vista, XP, 2003, and Outlook 2010. 2007, 2003, 2002.