An Outlook profile is consisted of basic email account information, such as email server name, ISP (Internet Service Provider) account password, and user name. The profile stores a unique key for Outlook Offline Folder (.ost file), which allows you to log onto Exchange Server mailbox and hence, synchronize the OST file. If the key is lost because the profile has been modified, this could make the OST file unusable with Outlook. It primarily occurs if the corresponding changes do not reflect in Exchange profile or administrator deletes the user mailbox. However, to retrieve the emails, you should consider your backup or use an effective utility that could perform Ost to Pst Recovery.
For instance, consider a situation when you unknowingly make some changes in Outlook profile that you use to synchronize with Exchange Server mailbox. After this you find that you cannot sync with Exchange and cannot open the .ost file.
Cause
Exchange Server makes an encrypted cookie from the corresponding mailbox of OST file using its ID. It then saves this cookie in your Exchange profile when you are logged into the server computer. Your Outlook profile contains this key, which is checked by Exchange each time when you try to access the .ost file. Thus, if you modify your profile, the key might get lost or replaced. As a result, you cannot authenticate to the server and the OST fails to open.
Solution
Outlook email profiles are stored in Windows registry. So, if you have a registry backup of time before you modified the profile, you can recover it by restoring the previous backup of Windows registry. After this, you need to force Outlook to use the restored profile using ‘When starting Microsoft Outlook, use this profile’ option of Outlook profile.
If the above step is not feasible, you should create a new .ost file to synchronize with Exchange. To recover emails from orphaned OST, it is suggested to use OST to PST Recovery applications. OST Recovery tools are powerful utilities designed to perform safe conversion of unusable OST file to Outlook usable PST file.
Stellar Phoenix Mailbox Exchange Desktop is a secure and advanced OST file conversion product providing rich set of features. The software enables systematic OST to PST Recovery 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.
