Outlook OST file is a useful feature for Microsoft Outlook users, using which they can work offline. It also serves as the valuable option for Exchange Server administrators for recovery. OST requires to be synced with Exchange Server for successful conversion to PST file and getting accessed by Outlook. For any reason, if the sync fails, the file may remain orphaned. The emails of such unusable OST file should be restored from backup. In case if backup is not present or exists in invalid state, you need to use a commercial tool that could efficiently Convert OST to make it accessible through Outlook.

Consider the following scenario:

1-You use Exchange Server 2000 configuration, which has user account named as ‘A’.

2-You reinstall Exchange Server on Small Business Server

3-The account ‘A’ starts dating clear back to the Windows Server

4-The login name of account ‘A’ changes to ‘B’

5-You observe Outlook creates a new .ost file and the original OST remains orphaned with no access to previous mails

6-When you try to rename this new .ost file and rename the original file name to of new .ost file name, it fails

7-When receive an error as below:

“filename.ost can not be accessed because it has been configured for use with a different mailbox”

Cause

The original OST cannot sync with the Server as the user has been renamed

Solution

You should try these solutions to solve the issue:

1-You need to check the backup status for all the required emails. If a valid and updated backup is available, you can use it to import all the emails to the new .ost file

2-In case of backup unavailability, you need to convert the orphaned .ost file to usable .pst file. A .pst file can be directly accessed with Microsoft Outlook. To do so, you should use a third-party Convert OST tool.

OST to PST tools are powerful utilities designed to perform secure file conversion of an orphaned Outlook offline file. These are are easy-to-use products with graphically rich interface and advanced features.

Stellar Phoenix Mailbox Exchange Desktop is a reliable and powerful OST file conversion product providing rich set of features. The software enables systematic OST to PST file conversion while ensuring recovery of all email objects, notes, journals, and others. It supports Outlook 2003, 2002, 2000, 98 and 97. The tool supports Exchange Server 5, 5.5, 2000 and 2003 versions.