Most of us are well aware of Outlook, which is a desktop mail client that offers mailing facility and other personal information maintenance such as contacts, notes,
calendars, etc. Outlook stores all of its profile data in a data file and there are two variants of the same, i.e. PST and OST. PST stands for Personal Storage Table,
which stores all the personal information whereas; OST is Offline Storage Table, stores the offline copy of the Exchange mailbox. OST files are created in Outlook when
it is configured with the Exchange server while PST is generated when Outlook functions individually and independent of the server.

OST File and Its Particulars

As mentioned above, OST files are created when the Exchange server is in offline mode. When the user want to access the server mailbox while not in connection with
Exchange server then offline mailbox has to be configured the Outlook with the Exchange server. Once if it is configured, then all the mails and works connected to the
server can be configured in the Outlook. Offline storage configuration is more of help when there is: no network, downtime of server, or when we are offline. With the
OST file, one can work with the mails anywhere without network; remembering that, OST files cannot be backed up individually since it is configured with the server.

While configuring with the server to create OST file “Cached Mode” must be enabled else, the OST file will not be generated. The OST files are the copy or replica of
the mailboxes stored in the Exchange server that serve as the cache.

Location of OST Files At:

Windows 7 and Vista

Drive:UsersuserAppDataLocalMicrosoftOutlook

Windows XP

Drive:Documents and SettingsuserLocal SettingsApplication DataMicrosoftOutlook

Need of Conversion from OST to PST:

Let us go through some of the reasons that make us choose to convert OST to Pst Files.

There may be failure of the server due to any error, virus or other malfunctions, etc. So, when there is a crash of the server the stored mailbox can be deleted making
its offline copy vulnerable.
To view the OST file can only synchronize with the Exchange mailbox to which it belongs whereas a PST does not come with limitations like that. Thus, conversion from
OST to PST files makes possible way and it is easy to use PST files on other machines via different accounts.

Manually How Can We Convert OST File to PST?

Outlook OST to PST files can be done manually but it is not much efficient as far as the quality of conversion/transfer is considered:

Method 1: Archive

MS Outlook 2013 has the facility to archive the folders or files. The user can archive the Outlook OST files to PST using the ‘Archive’ option available. All
information can be archived but, exception with ‘contacts’.

Outlook 2013 Mailbox Cleanup

Method 2: Export to New PST File

Using ‘Export’ option the user can easily transfer .ost files to .pst files. This option even provides to store the file in CSV and Excel format.

Open the ‘File’ seen on the top of Outlook
Select ‘Open and Export’ option from the Account Information
Export to New PST File

Select “Export to a file” option and proceed
Export to a file

Choose the option “Personal Storage Table (.pst)” and click “Next” button
Select the folder to be exported and then proceed
Choose the location and then click on “Finish”. PST file will be stored on desired location.

Method 3: Move to a New PST

The user can convert OST to PST by dragging the OST files to a newly created PST files. During dragging one should be make sure that file is .ost, .pst files cannot be
dragged. It is an easy way of converting.

Although the manual procedure works well but, there are few limitations that should be noted. If the .ost file is corrupted then, conversion from OST to PST won’t be
possible manually and also if the OST “orphan” i.e. if the server is detached then converting is not possible. So, need to rely on third party “software” which helps
in conversion even if the OST file is corrupted or orphan.