An Offline Storage Table (OST) file is the data file created for an Exchange Server account configured in the MS Outlook application. Apart from Exchange Server, the application will create an OST file for IMAP, Microsoft 365, and Outlook.com/Hotmail.com accounts. The OST file will save a synchronized version of your mailbox data in a data file on the computer. When the Internet is down and Outlook does not establish a proper connection, then it uses an OST file to access the mailbox information. You can write an email and it will remain in your outbox until the Internet is present again.
The changes will always remain synchronized and there will be no problem with email timings, contact creation, and to-do tasks.
If you want to add the same account in a different Outlook application on a different computer, then you can physically move the data file copied from its location and transferred to another computer.
Know the location of the Outlook OST file
If you had connected your Exchange Server, IMAP, and Office 365 account in Outlook, then you can use the Account Setting and check the data file location.
- Open the Outlook application and click the File option in the ribbon.
- The Info section shows the Account Setting option that you can click and choose Account Settings again.
- In the Account Settings wizard, choose the account whose OST file you want to access. Then, click the Data File tab and choose Open File Location.
- The wizard will redirect you to the Windows Explorer folder where all the OST files are saved.
Now, you can copy the OST file and transfer it to another computer using a transfer medium like Pen Drive, flash drive, etc.
When the Outlook application is not functional or accessible, then you can use Control Panel to access the data files.
- Open Control Panel and click Mail.
- If you click the Data Files button, then it will take you to the Account Settings wizard where you can choose the account and click Open File Location.
The file location will have the OST file that you can copy and transfer to another computer.
Even if you can transfer the Outlook OST file to a new computer, then you cannot open it manually in Outlook because Outlook supports PST files as an external data file only. It can export and import any user mailbox as a PST file only.
If you want to use the same account with the existing content of the mailbox, then you can export it in a PST file, then transfer that PST file, then import it into the Outlook application.
Export mailbox as a PST file
- Open Outlook and click File.
- Go to the Open & Export option, then choose Import/Export.
- Choose ‘Export to a file, then click Next.
- Choose ‘Outlook Data File (.pst)’ as the file type, then click Next.
- Select the folders that you want to use in the account at a different computer. You can also include subfolders and apply filters, then click Next.
- Choose the Options to handle duplicate items, then click the Browse button to select a destination folder for exported PST files. Click Finish.
After exporting and transferring the PST file, you can import it using the same method as Export.
Import PST file in Outlook
- Open Outlook and click File.
- Click Open & Export, then choose Import/Export.
- Select ‘Import from another program or file.’ Click Next.
- Select Outlook Data File (.pst) as the file type to import. Then, click Next.
- Click Browse to select the PST file, then click OK.
- Click Finish to finalize the import process.
A user may require to transfer OST or PST files when they are going to use the same account on different computers. Ideally, when you create an account on Outlook, then all the mailbox folders will be generated automatically. But, if you want to access Contacts, Calendars, and to-do tasks, then you should import PST files from the older computer.
In case, if the Outlook application is not working, then you should use a professional OST to PST Converter software to convert the OST file into PST format. It will protect and maintain the hierarchy of mailbox folders and help you in accessing contacts, to-do tasks, notes, and calendar information.