Outlook All Versions

By default, Outlook places each Offline Folders (.ost) file and Personal Folders (.pst) file that it creates in the %userprofile%\Local Settings\Application Data\Microsoft\Outlook folder. You can either use a registry value to change that default location, or you can manually create a new profile and specify the .ost filename and folder.

• .ost = offline folders file
• .pst = personal folders file

more details...

OST - Offline Folder Storage - A file that contains a local replica of a user's Microsoft Exchange Server-based folders (private and public) and forms. The OST is synchronized with the Microsoft Exchange Server copy for use while working offline. An OST is specific to a particular mailbox and cannot be accessed by other users of Microsoft Exchange Server.

PST - Personal Folder Storage - A file that may contain folders, messages, forms, files and other items. You can create any number of PSTs for use with a single profile. You can also designate a PST as the delivery location for incoming mail.

New Client Installation - If you are installing the Microsoft Exchange client for the first time, during the profile creation you will be asked if you travel with the computer. If you answer yes, an Offline Store provider is set up for you and a file, Exchange.ost, is created. The OST is where the offline folders will be stored.

Existing Client Installation - If this is an existing installation of the Microsoft Exchange client, you can create an offline store using the Offline Folder File Setting button in the Advanced tab of the Microsoft Exchange Server driver property page. If multiple users will be using a single computer, each user needs his or her own OST file.

On a default Outlook / Exchange configuration, the user wont have a pst file, but an ost file. All the stuff in their inbox will be on exchange and in the ost file right? If they want to back it up, they can export it to a pst file.

Change the location where your offline files are saved - Outlook 2003

  1. Exit Outlook.
  2. Click Start, and then click Control Panel.
  3. Double-click Mail, and then click E-mail Accounts.
  4. Click View or change existing e-mail accounts, and then click Next.
  5. Select the Microsoft Exchange Server account, and then click Change.
  6. Clear the Use Cached Exchange Mode check box.
  7. Click More Settings.
  8. Click the Advanced tab.
  9. Click Offline Folder File Settings.
 10. Click Disable Offline Use, and then click Yes in the dialog box that appears.
 11. Click Offline Folder File Settings.
 12. Click Browse, go to the location where you want to save your .ost file, and then click Open.
 13. Click OK.
 14. Select the Use Cached Exchange Mode check box.
 15. Click Next, and then click Finish.