Outlook creates two types of data files to store mailbox data – PST (for POP3 accounts) and OST (for IMAP and MAPI accounts). PST is a portable data file that you can open in any Outlook on any system. On the other hand, OST file is bound to the Outlook profile and computer on which it is created. So, you can’t open OST in other Outlook account or move an OST file to a different computer.

How to Open OST in Outlook 2016?

You can’t directly open an OST file in Outlook 2016. You can only access the OST in the particular Outlook application, in which it is originally created. However, if the OST is damaged or causing errors, then you can recreate the OST on your system.

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Recreate OST in Outlook 2016

To recreate OST in Outlook 2016, delete or rename the old OST from your system and reopen Outlook. The software will recreate the file automatically. Otherwise, follow these steps:

  • Go to Windows Control Panel > Mail (Microsoft Outlook).
  • In the Mail Setup window, click Show Profiles and select your Outlook profile.
  • Click Properties and click Email Accounts.
  • Select your email account and click the Change
  • Unselect Use Cached Exchange Mode checkbox and click More Settings.
  • Open the Advanced tab and click Offline Folder File Settings.
  • Select Disable Offline Use. In the window that opens, click Yes.
  • Click Offline Folder File settings and click OK.
  • Select Use Cached Exchange Mode Then click OK.
  • Click Next and then click Finish.

If you want to open an OST on another system, you need to first export the OST data to PST file and then import this PST file into Outlook on any system.

To export Outlook mailbox file in Outlook 2016 on another PC, follow these steps:

  1. Launch Outlook and open the File Go to Open & Export and select Import/Export.
  2. In the Import and Export Wizard that opens, select Export to a file option and click the Next
  3. Select Outlook Data File (.pst) and click the Next
  4. Select the folders that you want to export to PST. You can also select your email account to save the entire mailbox to PST.
  5. Select Include subfolders checkbox and click the Next button.
  6. Click Browse and enter the location where you want to save the PST. Then select the appropriate option under Options and click Finish.
  7. In the Create Outlook Data File window, set a password (optional) for the PST. If you don’t want to set a password, leave the password fields blank and click OK.

Once the PST file is saved, you can open it in Outlook 2016 on any system.

How to Open Orphaned OST File in Outlook 2016?

If you’re not able to access the Outlook account or the OST file is inaccessible, you can’t export items from the OST to PST via Outlook Import/Export wizard. In such a situation, you need to use a third-party OST to PST converter tool to save the file in PST format.

Some common scenarios in which you need to use an OST to PST converter tool are:

  • You’ve accidentally deleted some important emails from your account. However, you have an old OST file from which you can recover the emails.
  • The OST file has synching issues. If it’s large-sized, you may face difficulties in downloading it from the server. Converting the OST to PST with a third-party software is faster and more convenient.

Use OST to PST Converter to Open OST in Outlook 2016

To convert OST to PST, you can use Stellar Converter for OST software. It’s an advanced OST to PST converter tool that can convert all OST mailbox items, such as emails, contacts, tasks, etc. to a PST file. It can convert large-sized and encrypted OST files. Further, it saves the OST data in various other file formats, such as HTML, MSG, EML, PDF, and RTF.

The following are some salient features of Stellar Converter for OST:

  • Converts large and encrypted OST files to PST
  • Identifies and extracts specific items from the offline data file (OST)
  • Offers detailed preview of OST mailbox items before saving them
  • Converts multiple OST files in a single batch
  • Allows you to convert a large OST file in multiple sessions by saving scan data in a DAT file
  • Directly exports OST to Outlook, Office 365 account, and live Exchange (available in Technician edition)
  • Splits and compacts large OST (available in Technician edition)
  • Converts OST to PST, MSG, EML, RTF, HTML, and PDF

To convert OST file into PST by using the software, follow these steps:

  1. Launch the software. In the ‘Select OST File for Conversion’ window, click Browse to locate the OST file of your Outlook 2016. The OST file is usually located at the following location:
  • C:\Program Files (x86)\Microsoft Office\root\Office16

Note: If you don’t know the OST file’s location, you can click the Find button.

  1. After selecting the OST file, click Convert to begin the conversion process.
  2. After the file is converted, preview the file’s contents in the preview pane. Then select the items you want to save to PST.
  3. Under the Home button, click the Save Converted File
  4. In the Save As window, select PST from the options. Then click Browse to provide the location for saving the PST.
  5. Click OK to save the file. Once the PST file is successfully saved at the given location, the software will notify you the same.

Now, you can import the file into Outlook 2016 by using Import and Export wizard and access its data.

Conclusion

OST is an offline Outlook data file that is bound to the Outlook profile and the system on which it is created. To open it on any other system, you need to convert it into PST first. You can easily convert the OST to PST with Outlook’s Import and Export wizard. However, if the OST file is orphaned or inaccessible, you can use a powerful tool such as Stellar Converter for OST to convert the OST file into PST.

About the author

Abhinav Sethi is a Senior Writer at Stellar. He specializes in technical communication, industry research, and data collection for subjects such as email forensics and data science.

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