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Summary: This comprehensive guide explains the significance of OST files in Exchange mailbox data management and provides precise steps for changing their location using Group Policy across Outlook versions. It also highlights the importance of data recovery solutions like Kernel for OST to PST Converter.

The Offline Storage Table (OST) file serves as a repository for storing Exchange mailbox data on the local system when the cached Exchange mode is activated. Its significance lies in ensuring that Exchange data remains accessible to users even in situations where the Exchange Server experiences downtime. The OST file preserves all tasks performed in offline mode, and when connectivity is reestablished, it synchronizes and updates the stored data.

The default location of an OST file is –

  • C:\Users\AppData\Local\Microsoft\Outlook
  • C:\Documents and Settings\Local Settings\Application Data\Microsoft\Outlook

At times, it becomes imperative to relocate the OST file to a different location in order to free up space on the C Drive. In this discussion, we will explore how you can accomplish this task across various Outlook versions utilizing Group Policy.

How to change OST location in Outlook 2010?

To shift the location of an Outlook 2010 OST file to a Network Shared folder using a GPO, you must first acquire and install the Group Policy Administrative Template Files. These files can be obtained from the following location:

This tool includes an ‘\Admin’ folder and various versions of ADMX, ADML, and ADM files for Office 365 Administrative Templates. Once you’ve downloaded the file, navigate to the AMDX folder on the C drive of your Exchange Server 2012 R2, and paste the downloaded setup file there. Then, extract the file, and it will initiate the automatic installation process. Now, proceed with the following steps:

  1. Copy office14.admx file from the ADMX folder. Paste it at the location %systemroot%\PolicyDefinitions\.
  2. Copy the outlk14.adml file from AMDX\ADMX\en-US location and paste it at the %systemroot%PolicyDefinitions\en-us.
  3. Now, launch gpmc.msc and follow User Configuration>>Policies>>Administrative Templates>>Microsoft Outlook 2010>>Miscellaneous>>PST Settings.
  4. Here you will see Default location for OST files, and the Default location for PST files. You can change these settings and change the default location to a network shared folder.
For Outlook 2013, 2016, and 2019.
  1. Load the Outlook 2016 Template at the Group Policy.
  2. Go to Group Policy Management Console (GPMC), expand Domains, and then Group Policy Objects. Right-click to it.
  3. After right-clicking the Group Policy Objects, click Edit and it will open the Group Policy Management Editor.
  4. Follow User Configuration>>Policies>>Administrative Templates>>Microsoft Outlook 2016>>Miscellaneous>>PST Settings.
  5. Choose the option Default location for OST files and click ‘Enabled’ for the policy setting.
  6. Input the new location for the OST file and click OK.
  7. Using the same method, you can change the location for the PST file also.
Additional Group Policy Settings

There are many Outlook related settings you can change using Group Policy. Some of them are mentioned here:

  • Cached Exchange Mode Sync Settings.
  • This feature allows Outlook to locally synchronize email messages based on their message date. By default, Outlook syncs messages from the past 12 months. If you wish to remove this restriction, you can access the settings and choose ‘All’ from the synchronization options list.

  • Disallow Download Full Items
  • It turns off the Download Full Items option for Outlook.

  • Disallow Download Headers
  • It turns off the Download Header option in Outlook.

  • Disallow Download Headers the Full Items
  • It turns off the Download Headers then Full Items in Outlook.

  • Disallow On Slow Connections Only Download Headers
  • It turns off the On Slow Connections Download Only Headers option in Outlook.

  • Download Public Folder Favorites
  • It synchronizes Public Folder Favorites in Cached Exchange Mode.

  • Download shared non-mail folders
  • It synchronizes shared non-mail folders in the Cached Exchange Mode.

  • Use Cached Exchange Mode for new and existing Outlook Profile
  • It configures new and existing Outlook profiles to add in the Cached Exchange Mode.

Final Words

Modifying the location of the OST file can prove beneficial in specific scenarios; however, it’s not always an ideal solution, as it carries the risk of file corruption or inaccessibility. During the relocation process, users may inadvertently delete data from the OST file or even delete the file itself. While group policies assist in changing the OST file location, they may introduce accessibility challenges. In the event of errors, resorting to the ScanPST tool becomes necessary, as it can scrutinize the OST file for minor corruptions.

Considering the potential limitations of the ScanPST tool, opting for a professional alternative appears to be a prudent choice. Kernel for OST to PST Converter offers a robust solution for swiftly recovering inaccessible and deleted items from a corrupt OST file. If you find yourself unable to open or access data within an OST file, this software can assist you in retrieving those items. Furthermore, it allows for seamless integration of the resulting PST file into Outlook, ensuring a smooth transition after the OST to PST conversion process.

Kernel for OST to PST