Personal Storage Table (PST) and Offline Storage Table (OST) are Outlook data files created when configuring an email account in Microsoft Outlook. Whether Outlook will create, an OST or PST file depends on the email account. For example, if the email account belongs to a POP3 server, Outlook creates a PST file. However, if you add an IMAP, Outlook.com, Office 365, or Exchange Server email account, an OST file is created at a default location.
These Outlook data files store the mailbox items, such as emails, contacts, attachments, calendar items, tasks, notes, etc. The core difference between these two data files is that the OST is encrypted by default with MAPIEntryID GUID key while PST isn’t (unless encrypted manually). Thus, PST can be easily imported into any Outlook profile without any issues. However, if you have an OST file containing mail items you want to restore to your new Outlook profile, you must convert the OST into PST format.
In this article, you will learn different methods to convert the OST file into PST format. You will also learn steps to export individual mail items from an OST file to various file formats, such as HTML, RTF, PDF, EML, and MSG using Outlook options and a third party OST to PST converter software.
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Methods to Convert OST into PST
There are two different methods to convert OST into PST format. The method you follow will depend on the accessibility of your email account and OST file.
If you have an active email account and profile setup in Outlook with OST as a data file, you can export the mail items to PST format using Outlook Import/Export wizard.
However, if you have an old or backup OST file that you need to convert or an OST file that belongs to a deleted email account, you must use an OST to PST converter software.
Convert OST into PST via Outlook Import Export Wizard
To export mail items from OST file using Outlook Import/Export wizard, follow these steps:
- Open Outlook and go to File > Open & Export > Import/Export. This opens the Outlook Import/Export wizard.
- Select Export to a file and click Next.
- Select Outlook Data File (.pst) and click Next.
- Select all the mail items you want to export to PST format and click Next.
- Click Browse and select a location where you want to save the PST file. Click Finish.
- You may see a prompt to enter a password. You may enter one if you want to password-protect it. Otherwise, click OK.
- The mail items from your Outlook OST will be converted and saved in a PST file at your desired location.
Convert OST into PST using OST to PST Converter Software
If you don’t have access to your OST file or Outlook profile, you can use an OST converter software, such as Stellar Converter for OST, to extract all mail items and save them into a new or existing PST file.
In addition, the software also provides an option to save the converted OST file and mail items to HTML, PDF, RTF, HTML, EML, or MSG format. Further, you can export the mail items from an orphaned or inaccessible OST file directly to Office 365 or live Exchange Server.
Convert or Export Individual Mail Items to Other File Formats
Besides the OST to PST converter software, there are two other ways to export or save individual mail items in different file formats.
Use Outlook Options
In Outlook, you can export or save individual mail items in Text (.txt), Outlook template (.oft), Outlook Message format (.msg), HTML (.html or .htm), and MHT (.mht) file formats.
To export or save individual emails in any of the above-mentioned file formats, follow these steps:
- Open Outlook and double-click on an email or select the email you want to save in the HTML, OFT, MSG, MHT, or TXT file format.
- Click File > Save as.
- Choose a location and enter the name for the email file.
- From the Save as type: dropdown, choose the desired file format.
- Then click the Save button.
Repeat the steps to save other emails individually.
Tip: You may use the Shift or CTRL key to select multiple emails at once and export or save them to TXT format. HTML, OFT, MSG, and MHT file formats are not available when you save multiple emails at once.
Use XstReader (Open Source tool)
XstReader is an open-source OST/PST file viewer tool that allows you to save individual or all mail items in HTML format or mail properties in CSV format. There are no other save options available. The steps are as follows:
- Download the XstReader.zip file and extract it to a folder on your Desktop.
- Open the folder and launch the XstReader.exe program file.
- Click the Open button (located at the bottom left corner) and then browse to select the OST file containing mail items you want to convert.
- The program will load all mail items. Right-click on any mail items or email folder and click Export Email… or Export Properties…
- If you select Export Email…, the email will be saved as an HTML file. You can use the CTRL key to select and convert multiple mail items to HTML at once.
- If you select Export Properties…, the message with all message properties will be saved in a CSV file. However, it does not save the mail content but only properties.
It’s recommended that you export and backup mailbox items from your Outlook account to PST format. This will allow you to restore the mail items if something goes wrong with your Outlook program, profile, or the associated OST file. In addition, it can help prevent data loss and restore the mail items even if your profile is removed or disabled from the server. However, if you have an OST file you want to convert into PST format, there’s no other way but to use an OST to PST converter software, such as Stellar Converter for OST. You may also use the XstReader to read or save the OST file’s mail items to HTML.